New Zealand's government has ordered an investigation into claims that the security services illegally spied on Maori individuals and organisations.
Ms Clark said she did not believe the allegations
The investigation follows a complaint by a leading Maori member of parliament.
Prime Minister Helen Clark said she did not believe the allegations, but did not want people to suspect a cover-up.
Maori, New Zealand's indigenous people, make up about 15% of the country's 4-million strong population.
Co-leader of the Maori Party, Tariana Turia, asked for the investigation after allegations were carried in a newspaper that the Security Intelligence Service (SIS) ordered the monitoring of unnamed Maori individuals and organisations several years ago.
The allegations were based on information from three spies, the Sunday Star Times newspaper reported.
Ms Clark, who is responsible for the SIS, said she doubted the claims were true, but agreed that the inspector general of intelligence and security, Paul Neazor, should investigate.
"I have readily agreed to that because I think it's time the people throwing the mud put up or shut up," Ms Clark said.
"I do not want any suggestion that anyone is covering anything up."