Opposition parties say the Prime Minister should still consider standing John Banks down as a minister despite a police decision not to prosecute him over his mayoral campaign electoral return.
Following an investigation, police say there is not enough evidence that Mr Banks falsely recorded donations to his 2010 Auckland mayoralty campaign as anonymous.
Labour leader David Shearer says John Key should stand the ACT MP down as a minister, while Green co-leader Metiria Turei says Mr Key needs to think long and hard about whether Mr Banks should be a minister in his government.
Mr Shearer says John Key promised high ethical standards from his ministers and should let Mr Banks go.
"It's blatantly obvious he got off on a technicality," Mr Shearer says. "Everybody in New Zealand knows what happened. He asked for money, he received the money and then he forgot - and he's off on a technicality."
Mr Key says however that he won't stand Mr Banks down, saying the original complaint by Labour MP Trevor Mallard was politically motivated and Mr Banks has been shown to have complied with the law.
Sky City, Dotcom donations investigated
Police investigated complaints in respect to donations from Sky City and the internet millionaire Kim Dotcom and the donation of radio advertising from a donor who wishes to remain anonymous.
They say they have established that he solicited the donations that a campaign volunteer subsequently recorded in his electoral return as anonymous, but that he sought and received confirmation the returns were accurate before he signed them off.
In a letter to Mr Mallard, police say there is insufficient evidence on any of the three complaints to prosecute on the basis that the return was submitted knowing it was false.
Assistant Commissioner Malcolm Burgess told Checkpoint the volunteer who compiled the return followed an appropriate procedure. He says the volunteer told Mr Banks the return was recorded correctly, and Mr Banks acted within the law in signing it off.
More political scrutiny expected
Mr Banks has acknowledged the professional way in which police approached the investigation. He says his campaign team maintains its 2010 electoral affairs were conducted within the law, and members are glad these matters can now be put behind them.
In a statement he says he will make no further comment about the matter.
He can now carry on as Minister of Regulatory Reform and Minister of Small Business without the worry of a police investigation, but Radio New Zealand's political editor says he can expect more political scrutiny of the issue.