UPDATED 9.07AM: A combined show of force from the Labour and Green parties is swearing to change the government, but few policies are so far forthcoming.

LISTEN ABOVE: Labour leader Andrew Little speaks to Andrew Dickens

The two opposition parties shared a platform yesterday afternoon in Auckland to deliver their 'State of the Nation' speeches. They have agreed to work together ahead of this year's election.

Labour leader Andrew Little unleashed a piercing critique of Prime Minister Bill English, describing him as a "competent bean counter" but "not a leader."

"Here's the truth," Little said. "National is out of ideas and out of touch. They've got nothing new to offer."

Both Little and Green Party co-leader Metiria Turei put the government's performance on housing, education, health, and jobs in the spotlight.

Turei said the National Party does what is easy, won't do what is right, and pledged that her party will, however, do both.

A policy platform wasn't revealed during the speeches, though Little promised some joint policies would be on the way, signalling greater co-operation on economic policy and principles.

"New Zealanders will have in front of them, and get a very clear understanding about what constraints are put on what we're doing, and what they can expect in terms of economic management," Little said after delivering his address.

"What we have to show voters is that there is common ground," Labour MP Jacinda Ardern said this morning. "That to me is just being transparent." 

The lack of policy has been criticised by Finance Minister and National Party campaign chair Steven Joyce.

"I remember back to when we were in opposition and if we'd rocked up at the beginning of election year and said 'Actually we don't like the other guys and we haven't actually got anything new to say, we just think that people should not like them either and they should vote for us' - I don't think that's a particularly compelling message to start the year," Joyce said.

Little "hasn't even thought about" whether it might need to call on the support of Winston Peters' New Zealand First party if a coalition government needed to be formed, nor whether someone like Peters would take a Deputy Prime Minister role over Turei.

"I'm not going to negotiate the formation of a government before the voters have their say."

No date has been set for this year's election but it's expected to be in the latter half of the year, with September 23 thrown up as a possible date.

Prime Minister English is expected to announce the date as early as next week.