National's leader John Key says a deal with the Greens is possible after the election but they would have to accept his party's "balanced agenda".

The Greens are keeping their options open and decided at their annual conference last weekend to wait and see all the environment policies of the main parties before committing themselves to supported either Labour or National.

Mr Key said today the Greens had been looking at the Government's environment record and didn't like it.

"No government has cut down more trees in New Zealand in the last four years than this government," he said.

"There's been massive deforestation in recent times ... and three-quarters of all new electricity generation undertaken by Labour in the last nine years has been thermal -- coal or gas."

Mr Key said he couldn't rule out reaching an agreement with the Greens.

"Never say never. We've got a balanced agenda," he said on TV One's Breakfast programme.

"The environment is important, New Zealanders value it and it's important for our international reputation but we also need a stronger economy to deliver better living standards.

"If they can live with a balanced agenda, then sure we can have discussions with them. But they tend to come from a slightly different perspective from us."