Key Points:

Labour leader Phil Goff has said he will work with other parties to review the Electoral Finance Act.

The Act was designed to make election donations transparent. But it has drawn criticism from lobby groups who say campaigning in an election run-up has become frustrating and so confusing it is almost impossible for them to know what they can and can't do.

Electoral Commission head Helena Catt has described the law as having a "chilling effect" on political debate in New Zealand, while several third parties said uncertainty about what is caught in the net of "election advertising" muted normal public debate this year.

Mr Goff told Radio New Zealand this morning any Act that was "constitutional or electoral" should have had the consensus of all parties, something Labour did not have when it introduced the legislation.

"I don't think the way that the Electoral Finance Act was passed or necessarily its specific detail was as good as it could have been," he said.

"I think we do need to look at that again. I think we need to look at that in a way that involves all parties.

Mr Goff said the reasons underlying the Act were still valid.

"What I would like to see is a system where democracy works but doesn't rely simply on the power of the dollar and you don't have some clandestine funding which was the real concern that lay behind the Electoral Finance Act," Mr Goff said.

The Act widens the definition of election advertising, caps spending by third parties and requires them to register and extends the election period from three months to the whole of the year.

It was passed in response to an initially clandestine $1.3 million campaign by Exclusive Brethren members in support of National at the 2005 election.

National - which opposed the Act along with United Future, the Maori Party and Act Party - has promised to repeal the legislation, but keep its tighter provisions on anonymous donations.

It has not spelt out exactly how it will go about making changes, but could wait until the usual review of the election by Parliament's justice and electoral select committee is completed.