Political parties are facing fresh scrutiny over anonymous donations amid questions about money received by New Zealand First leader Winston Peters.
The matter has arisen following confirmation on Friday of a $100,00 donation towards the legal costs of an electoral petition by Mr Peters in 2006 and a newspaper report that his party received up to $150,000 from a prominent racing industry family.
The National Party has declared it received $493,000 through trusts and another $40,000 in anonymous donations in the last financial year.
Labour has declared it received $230,000 last year through law firms and "undisclosed clients".
Under the Electoral Finance Act, anonymous donations under $10,000 are permitted as long as they are not from the same person.
National Party leader John Key says he does not know who his party's donors are.
Prime Minister Helen Clark says Labour would be delighted to end the practise of anonymous donations if there was support for the state funding of political parties.
Mr Key says National will repeal the Electoral Finance Act if it wins the election and replace it with legislation which is easier for political parties to interpret. But he says it is too early too look at issues such as state funding.