The Prime Minister says there are accusations against his minister John Banks regarding his 2010 campaign for the Auckland mayoralty but no evidence.
John Key says he will not be standing down the ACT party leader from his ministerial duties for allegations he falsely declared large campaign donations.
Police are investigating claims John Banks declared $65,000 of donations from the SkyCity casino and Kim Dotcom to his 2010 Auckland mayoral campaign as anonymous, when he knew who they were from.
Labour leader David Shearer is calling for Mr Key to stand down Mr Banks from his roles as Small Business and Regulatory Reform Minister, and associate ministerial posts, until fully investigated.
But Mr Key says he will not be taking any action because Mr Banks has given him his word he has not done anything which has broken the Local Electoral Act.
He says there is no evidence Mr Banks has broken the law - just accusations, and people making the claims are free to test them with the police.
John Banks says he has nothing to hide and he welcomes an inquiry into donations to his campaign for the Auckland mayoralty in 2010.
The National Party says it does not believe it has received large donations from SkyCity or Kim Dotcom.
National president Peter Goodfellow says the party will report donations of above $15,000 to the Electoral Commission on Monday.
But he says he does not expect either SkyCity or Mr Dotcom to be on that list.
Mr Goodfellow says he has never met Kim Dotcom - who United States authorities are trying to extradite from New Zealand on internet piracy charges - and he is not aware of any direct donation from him.
Mr Goodfellow says transparent donations are central to the integrity of the election system, so people can be assured no-one is buying a favour.
But in an interview on Q + A on Television NZ on Sunday, Mr Banks refused to comment on claims he asked Mr Dotcom to split $50,000 into two parts so it could remain anonymous.
Mr Banks said when he signed the declaration for the mayoralty campaign, he signed it in good faith and in the knowledge that as a Justice of the Peace it was true and correct.
He said he has nothing to fear and nothing to hide.