UPDATED 6.46PM More meth has been found by police among sand dunes in Northland, adding to what is already the largest meth seizure in New Zealand history.

LISTEN ABOVE: Superintendent Russell Le Prou talks to Larry Williams

Police enquiries have been ongoing since the record find was discovered in the back of a campervan on Sunday night.

Coordinates in a GPS device found inside a Toyota Prado led police to sand dunes on the Hukatere region of 90 Mile Beach, close to where the original boat was left abandoned.

There they dug into the sand, and found another stash of bags full of methamphetamine, taking the total amount recovered now to 494 kilograms.

The initial meth haul was 448kg, meaning yesterday’s find added a further 46kg to the bust.

Police can also confirm that a second boat has been seized as part of the operation.

This boat was located at Ahipara address and was found damaged on a trailer, police said.

Police aren't ruling out the possibility an international drug ring is behind the enormous quantities of meth found.

Three men, aged 19, 26 and 31, have appeared in Kaitaia District Court, charged with possession of methamphetamine for supply and importing methamphetamine.

Judge Sharp remanded them in custody till July 6th and granted interim name suppression.

The original quantity of the drug was valued at $500 million and was found in the back of a campervan.

It was discovered  after members of the public reported suspicious vehicles in the area, and people trying to launch boats off the Far North's west coast.

A number of mesh bags were found in the boat on Sunday morning.

The abandoned boat on 90 Mile Beach that led to the record-breaking methamphetamine haul (Supplied)

Police officers then began searching for a Toyota Prado and a rental campervan seen in the area.

When they found the campervan, they found it crammed with 448 kilos of the drug packed into plastic bags.

Two men, who saw the search underway and fled in the car, were arrested and taken back to Kaitaia Police Station.

A third man in the campervan was apprehended by police.

District Commander Superintendent Russell Le Prou said it's difficult to imagine just how big the seizure is.

"It's more than probably double three times more than anything we've seized in one lump before. This is significant, this is huge."

He said police and the community are buzzing after the seizure.

"It's the harm that this causes I think that's the biggest buzz, and it can't cause that harm because we have it."

The record breaking 448 kilos of meth outstrips the total combined amount of the drug seized in New Zealand last year.

Police Association President Greg O'Connor said he wouldn't be surprised if more large stashes are out there.

"The fact that the supply and cost of P hasn't changed in years would indicate there are plenty of shipments like this getting through."

Mr O'Connor said P is a growing problem and we need to address organised crime and meth addiction to combat it.

"These drugs would have ended up on the New Zealand market and that's why New Zealanders should be very concerned because if you get these, you have to wonder what is getting through."

Massey University's Dr Chris Wilkins said the bust doesn't particularly come as a surprise.

He said there was some skepticism when annual monitoring had been picking up increases.

But, he said, as large seizures are being reported it's clear they were monitoring real changes.

LISTEN: Police Minister Judith Collins talks to Larry Williams

Police Minister Judith Collins said the bust was “wonderful”. She had been given a heads up on the operation last night.

“It was so exciting - local police working with a local community. I think it has all the hallmarks of when the Rainbow Warrior bombers were caught, it’s basically local people saying to the police, ‘oh, this looks a bit funny.’”

Ms Collins said it was “absolutely” concerning that such a large amount of drugs were in New Zealand, and in the next few days more details would emerge.

“But I wouldn’t be surprised if there was gang involvement.”

Asked if it was concerning that any boats used had not been picked up coming into New Zealand waters, Ms Collins said doing so could be difficult, particularly if boats had not been in ports here.

“I think there’s still work going on about exactly what was happening. But it’s pretty clear that there was a pickup from either a yacht or a container ship or something like that that had been organised.

“And I’m sure once the details come through we will all sit back and think, well these are significant risks but I would also say to offenders and people planning to do this - watch out, the locals are watching you, and will, thankfully, talk to police and let them know.”

Ms Collins said she did not know where the drugs may have come from. Asked if any boat could have come via the Pacific Islands, she said it “was probably further north than that”, but she was not sure of the location.

Prime Minister John Key said the police should be congratulated.

“What it shows you is the extra resources and authority that we have given them, is allowing them to be successful, because this is the second very significant haul you have seen in recent times.

“I think it also answers some of the questions of where this precursor is getting in to New Zealand, and where the police need to focus their attention.”

Mr Key said, according to limited information given to him, a boat that may have been used by the criminals did not go through Customs, but was moored offshore.

Mr Key said the size of recent meth seizures had been “alarming”.

“I think they indicate to us that there is more product coming in, and today’s work by the police might answer some of those questions.

“We have been concerned about some anecdotal evidence of more P on the streets.”

Asked about the availability of P precursors in China, Mr Key said his understanding was it wasn’t illegal to buy them in China, but was illegal to have them sent to New Zealand.

“I think our authorities have been speaking to the Chinese authorities, but it is not illegal for someone to go and buy it over there.”

Labour leader Andrew Little said New Zealand had a meth problem, something that was well established and not helped by a lack of police resourcing.

“We are going to see more of this I suspect. We need a police force that is supported and equipped and geared up to go after that insidious drug.”

Customs manager investigations, Maurice O'Brien, said Customs was involved in the ongoing investigation, and was looking at several aspects of the case.

This included vessels of interest, and how the drugs came into the country.

“There have been ongoing developments as a result of the seizure and enquiries, which we are continuing to investigate.”

Previous meth busts

• 2006 — Operation Major 10 is named for the previous largest methamphetamine bust in New Zealand, when 95kg is seized at Auckland Airport.
  
  
• March 2015 —  Detectives and customs investigators working on Operation Wand seize 83kg of meth, with an estimated street value of up to $83m, following search warrants around Auckland. The haul includes the discovery of $20m worth of meth at a clan lab in Pakuranga.
  
  
• March 2015 —  In Operation Sorrento, police and customs seized $40 million of methamphetamine while carrying out searches across Auckland. Combined, Operation Sorrento and Operation Wand lead to the arrests of nine people — seven Chinese or Hong Kong national and two New Zealand citizens — who were charged with a combination of methamphetamine related charges, including importing, supply and possession.
  
  
• March 2016 —  Customs found 40kg of methamphetamine in a shipping container at Ports of Auckland. The drugs were hidden inside marble table-tops. More than $1m cash, and cars, including a Ferrari, a Lamborghini, a BMW, a Porsche and a Mercedes Benz, were also seized. Four men — two New Zealanders and two foreign nationals, were arrested and faced charges related to the importation and supply of the drug.