New Zealand police have called in the serious fraud watchdog after allegations the leader of country's largest political party tried to hide a donation.
Former centre-right National Party member Jami-Lee Ross last year quit and laid a complaint with police alleging his former boss and the leader of the opposition, Simon Bridges, asked for a $NZ100,000 ($A96,739) political donation to be divided up to avoid revealing its origin.
Bridges has firmly denied any wrongdoing.
On Tuesday, without naming any of those involved or other details, New Zealand police said they had referred a complaint about electoral donations in October to the country's Serious Fraud Office.
The fraud office confirmed it was looking at the matter but that it did not comment on ongoing investigations.
Bridges on Tuesday told media the complaint was a matter for his party to handle and that he was confident his hands were clean.
"It is a matter for the National party and a matter for them to cooperate with the SFO on," he said.
A party spokesman declined to comment, but pointed to earlier statements which said there had been no $100,000 payment and eight donations had been received.
After being accused of leaking against his leader, Ross retaliated in October by telling reporters Bridges had been offered a donation by businessman Yikun Zhang but that it turned up in a series of smaller payments under different names.
Now an independent member of parliament after being expelled by National, Ross on Tuesday said he understood investigators were tracing the origins of the money.
Under New Zealand law, only political donations of more than $15,000 need to have their source declared.
Bridges has previously said he had dinner with Zhang, but that the $100,000 donation came from a number of individuals and that Ross' claims were baseless.
There is no suggestion Zhang acted improperly in any way.
But the saga raised questions about the donor's connections to the Chinese government - with reports he spent five years as a member of the Communist Party's Consultative Conference in Hainan Province - and prompted debate about whether New Zealand's political system needed more transparency surrounding donations.
"We do need to control political donations by limiting them, making them more transparent and actually banning foreign donations," Green Party MP Golriz Ghahraman said.
A New Zealand parliamentary select committee is currently reviewing the country's last election and looking into risks of foreign interference.
