New Zealand's government has appointed a tax expert to review its disclosure rules for foreign trusts and says it's open to considering changes.

The move represents a change after Prime Minister John Key last week rejected the characterization of the country as a tax haven.

The Washington-based International Consortium of Investigative Journalists identified New Zealand as among 21 tax havens used by Mossack Fonseca, the Panama law firm at the center of the offshore accounts scandal.

The review will be conducted by John Shewan, a former New Zealand chairman of accounting firm PricewaterhouseCoopers. He has been asked to report back to government ministers by June 30.