Rivalries between Labour and a potential coalition partner are deepening just days from the election.

Greens leader Russel Norman says his party could work with a National-led Government.

"The most important role we would play where National was the Government was as the opposition and the lead opposition party," says Greens co-leader Russel Norman.

However, Mr Cunliffe told ONE News in Hawke's Bay today he thinks "it's a nonsense or at best wishful thinking".

With Labour's support stalling, the Greens are increasingly focued on upping their own party vote with some tough talk.

"The Green Party's has got good momentum and is growing...I mean Labour is a different story but that's an issue for them," says Mr Norman.

The Labour Party admits backroom conversations have taken place between Labour and the Greens to ensure it's not every party for itself.

"They've reassured us they'd be happy to support a Labour-led Government," says Mr Cunliffe.

But the Greens aren't ruling out an arrangement with a National-led Government.

"We've said that it's highly unlikely that we could support national on confidence and supply. If they were the Government then obviously we'd try to work with them wherever we could to get good green change," says Mr Norman.