Seven weeks after they were selected to the jury, the five men and seven women have finally retired to consider their verdicts.

They left Courtroom 1 at 1pm (2am NZT) and will be sent home if they do not reach a unanimous decision by 5.30am (NZT) today.

If the jury are sent home tonight, there will be a two day break and they will not sit again as a group until Friday.

Justice Nigel Sweeney has directed them to first consider the perjury charge against Cairns and they must be sure of the evidence of at least two of the three key Crown witnesses - Brendon McCullum, Lou Vincent and Ellie Riley.

If they are not sure Cairns was involved in match-fixing, the jury must find Cairns not guilty and the case is over - they do not need to consider the second charge of perverting the course of justice.

But if they convict Cairns, the jury can then turn their attention to the perverting the course of justice charge laid against Andrew Fitch-Holland and Cairns.

This charge arises from the Skype conversation where Fitch-Holland tried to persuade Vincent to give a statement to support Cairns' libel case against Lalit Modi.

In order to convict him, the jury must be sure Fitch-Holland knew Cairns and Vincent were involved in match-fixing and also that he asked Vincent to provide a false statement.

If Fitch-Holland is acquitted, Cairns will also be found not guilty. If found guilty, the jury can then consider whether Cairns and Fitch-Holland conspired together in a "joint enterprise" to obtain the statement.

In his final words to the jury, Justice Nigel Sweeney said inevitably there would be vigorous debate but urged them to listen to differing views.

"There is no pressure of time. It is by that route you can return true verdicts according to the evidence."

His closing address to the jury was spread over three days and summed up the evidence heard over the past seven weeks, as well as how to apply the law.

After previously talking about the evidence of Vincent and Riley - including a strong warning about the credibility of Vincent - Justice Sweeney turned his attention to the third key Crown witness.

In April 2008, Brendon McCullum was 26 and about to make his debut for the Kolkata Knight Riders in the inaugural Indian Premier League tournament.

His friend Chris Cairns was 37 and the captain of the Chandigarh Lions in the Indian Cricket League, which was unsanctioned.

Cairns was in the middle of the ICL World Series held in Hyderabad and said he flew to Kolkata for promotional work, possibly on behalf of the diamond company he worked with.

Ricky Ponting, the Australian captain, was also playing for Kolkata in the IPL.

He and McCullum were having a drink in the hotel bar when the New Zealander received a telephone call which lasted about five minutes.

McCullum told Ponting it was "Cairnsy" calling about a "business proposition", a comment of which Ponting was 100 per cent sure.

Ponting would not describe McCullum as naïve or vulnerable, but said the younger man might not have known how spot fixing worked in 2008.

"I understood what spot fixing was in 2008 but I wouldn't expect McCullum to know as much at the time, or even know about match or spot fixing at all".

The former New Zealand teammates met in Cairns' hotel suite and shared a bottle of wine with a meal of curry.

McCullum said he expected Cairns to talk about a legitimate business proposal, but instead asked if he knew anything about spot fixing.

"I knew via murmurs in the cricket world it was about manipulating part of the game but I didn't know what it was," Justice Sweeney quoted McCullum as saying.

McCullum said Cairns pulled out a piece of paper to explain how it worked.

"I understood he was talking about underperforming, which is not honest," Justice Sweeney quoted McCullum as saying.

"I was shocked. I initially thought he was joking. He was relaxed and said all the big boys were doing."

McCullum said Cairns said he had a team "working for him" which included Daryl Tuffey and Lou Vincent, but Justice Sweeney pointed out those names were not mentioned until McCullum's third statement.

McCullum said Cairns said he could earn between $US70,000 and $US180,000 every time he underperformed.

"McCullum said he was pretty shocked. Looking back, he wished he said no straight away," said Justice Sweeney.

"When I left, I said I would think about it. I just didn't want it to be true. I considered him to be a friend. I didn't want to rat on him," Justice Sweeney quoted McCullum.

"If I kept it to myself, no one would know about it and there would be no harm."

Justice Sweeney said McCullum was unsure why Cairns thought he might be susceptible to a match-fixing approach.

"Oddly, it was endearing that he trusted me enough to make the approach," McCullum said in evidence.

If Cairns had made a corrupt approach to McCullum, Cairns expected McCullum would raise the alarm as "all players were well aware of the need to report."

Justice Sweeney said Cairns accepted he may have explained spread betting, but did not equate spread betting with match-fixing.

"I did not want to recruit him...it was simply an occasion where two internationals, one current, one former, were meeting up as mates," Justice Sweeney quoted Cairns as saying.

McCullum then joined his New Zealand team mates on a tour of England in May.

He and Cairns crossed paths at a match at Lords, firstly in the New Zealand changing rooms and also at the Royal Kensington Hotel where the Black Caps were staying.

McCullum accepted the atmosphere was fine. Justice Sweeney said the implication by the defence was, if everything was fine, the atmosphere was inconsistent with a fixing approach in Kolkata.

On the morning of a match between New Zealand and Worcester on June 11, McCullum said Cairns called him and invited him to breakfast.

The met at the Baleros Café for about 20 minutes and seen together by a cricket fan, Dr Michael McCabe.

In giving evidence, McCullum said he agreed to meet as Cairns was "not aggressive" in the previous approach and was confident he could refuse.

"I should have said no to meeting him at all. I didn't want to see him and should have thought if I didn't report it, it would be bad for me," Justice Sweeney quoted McCullum as saying.

"I didn't feel threatened, I felt I could deal with it."

Cairns denied a second fixing approach and said the Worcester breakfast was a social occasion to talk about cricket, as New Zealand had been "pounded" by England and the tour had not gone well.

"I did not ask if he changed his mind."

Four days later, there was another match between New Zealand and England.

Again their paths crossed but nothing untoward happened, said Justice Sweeney.

"I think I was scared to come forward, he was someone who I idolised," McCullum was quoted as saying.

Following his return home from the England tour, McCullum asked his agent Leanne McGoldrick whether she thought New Zealand players in the ICL were involved in fixing, then specifically mentioned Cairns.

He then told Mrs McGoldrick about the alleged approach.

Soon after, McCullum told Daniel Vettori and Kyle Mills on a tour of Bangladesh in 2008, then Shane Bond.

The four people remembered different details but understood Cairns allegedly approached McCullum to fix matches.

However, Justice Sweeney pointed out, McCullum took part in a charity walk organised by Cairns in August 2008. Cairns, McCullum, Vettori and New Zealand coach Mark Greatbatch also played a round of golf together in Dubai.

Justice Sweeney said Vettori thought twice about playing golf with Cairns. But Cairns was still a friend and an opportunity to play an amazing golf course. "It was easier to do than not to do," Vettori was quoted as saying.

Justice Sweeney said Cairns also socialised with Black Cap players at a party in India where some of the players - not Vettori, McCullum or Cairns - were "overly enthusiastic with the ladies".

Vettori called Cairns the next day worried about photographic evidence.

February 10, 2011 was a very important date, Justice Sweeney said.

The New Zealand team listened to a corruption education talk by John Rhodes, of Anti Corruption and Security Unit in the ICC, before a warm-up match ahead of the Cricket World Cup in India.

McCullum, Vettori, Mills and Daryl Tuffey were in the squad, Justice Sweeney noted.

At the end of the talk, McCullum canvassed Vettori and Mills' opinions and decided he should report the alleged 2008 approaches.

He gave a statement in question and answer format to Mr Rhodes and Justice Sweeney reminded the jury they could read what he said.

The judge noted McCullum said the conversation with Cairns "stunned him" and asked the jury whether that was a reaction to match-fixing or an innocent conversation about spread betting.

McCullum said he did not know how much to include in the statement.

Justice Sweeney said McCullum did not mention meeting Cairns in Worcester, but there was no dispute it happened.

John Rhodes said McCullum "presented as a very nervous young man".

"My impression was he was struggling in relation to his relationship to Chris Cairns. I formed the view he was clearly talking about an illegitimate approach."

Mr Rhodes said the "inference was clear" this was an approach to underperform but it was not for him, in taking the statement, to put specific words in McCullum's mouth.

The ACSU and the ICC did not actively investigate Cairns after McCullum gave his statement.

Sir Ronnie Flanagan, ACSU chairman, said there was no question of the McCullum statement "being put into the cupboard and forgotten about".

Instead it was analysed by software and formed part of a file on Cairns containing some information which went "beyond rumour".

The ICC did not pursue an investigation against Cairns in 2011 because the ICL had folded and Cairns was retired.

As for McCullum, he was not disciplined for the delay in reporting because he came forward voluntarily.

After Lou Vincent was interviewed by John Rhodes in September 2013, the ACSU investigator re-interviewed McCullum in November 2013.

His second statement did not mention Ricky Ponting or the names of Lou Vincent or Daryl Tuffey, but he did mention them in a third statement the following year.

McCullum never saw any sign Tuffey was involved in match-fixing for New Zealand.

Vettori said the New Zealand selectors discussed the rumours about Daryl Tuffey, but decided he could not be dropped on rumour alone. Two other selectors, Mark Greatbatch and Glenn Turner, did not recall such discussions.

Justice Sweeney said McCullum made his third statement in March 2014 to the Met Police, which again contained further details.

The judge said the jury needed to decide whether McCullum's account was deliberately changed to serve his own interests, as the defence suggested.

Or was it because McCullum was asked questions more carefully in his second and third interviews, or innocently recalled more details.

"It's a matter for you."