The Government is hiring an international tax expert to independently examine New Zealand's tax laws in the wake of the Panama Papers revelations.
Prime Minister John Key told Paul Henry he's taking a paper to Cabinet this morning proposing the appointment. He says changes may be necessary.
Opposition parties say a wider scale investigation is needed to help guard against a whitewash.
But Mr Key says he doesn't support Winston Peters' call for a Commission of Inquiry.
"We're ranked in the top 20 in the world for disclosure," he says.
"Trust firms have to know the source of their revenue and they have to keep good records as they are regularly audited.
"If there can be improvements, we'll make improvements and we'll get this independent voice to look."
Mr Peters says while Mr Key's changing stance is welcomed, his solution won't be the answer.
"Unless the so-called expert has the respect of both Transparency International and the UK Tax Justice Network, then it will not allay the fears and the claims being made about New Zealand's position as a tax haven," the New Zealand First leader says.
"Clearly from expert international comment our system doesn't have integrity anymore and information emerging from the Panama Papers should suggest to the Prime Minister and his Cabinet that political damage control measures won't fix this cancer on our reputation as a country."
He claims Mr Key knew in 2011 about the Santa Tereza case when Geoffrey Taylor linked New Zealand company SP Trading to smuggling 35 tonnes of North Korean weapons into Iran.
"A principal for Santa Tereza in a plea bargain in Brazil admitted the money laundering operation that he was involved in," Mr Peters says.
Cases like that mean he should take the issue "deadly seriously".
The Green Party also wants the inquiry to be wider to ensure it's not a whitewash.
Co-leader James Shaw says Mr Key is in "damage control" over foreign trusts.
"While I welcome the Prime Minister's U-turn on New Zealand's foreign trusts, appointing a single tax expert is unlikely to lead to the kinds of reforms we need to protect our country's reputation.
"The Prime Minister needs to move from damage control mode to a meaningful reform of our secretive foreign trust regime."
A wider inquiry would need the input of Inland Revenue, transparency and anti-corruption experts, international tax law experts and also from the public, he says.