The National Party president is as confident as he can be that his party has not received any donations from money earned from corrupt activities.
Labour leader Andrew Little told Radio New Zealand's Morning Report programme his party was offered "handsome" donations by Chinese donors when he was party president.
Mr Little said he had two approaches from potential Chinese donors.
"I wasn't satisfied about the origins of their funds, I had a hunch it wasn't appropriate to accept them and we didn't accept them."
The revelation comes after Chinese President Xi Jinping, on a visit to the country last month, asked New Zealand to do more to apprehend corrupt officials who he says have fled here from China.
Mr Little said it could not be ruled out out that other political parties had benefited from donations from people from China who have been corrupt.
National's President, Peter Goodfellow, said the party has turned down some donations because of concerns about where the money came from, but none linked to corruption in China.
He said he was as confident as he can be that all National's donations have come from legitimate sources.
"Certainly we disclose all of our major donations, you're able to see who those people are, the others are all within the disclosure limits and I'm certainly not aware of any that would cause concerns."
Mr Goodfellow said National did not have the resources to do in-depth investigations into individual donations.
Mr Little told Morning Report he did not refer the approaches from Chinese donors to police because that was not his job.
"Certainly in the Labour Party when I was party president we were approached being offered handsome donations - we turned them down, but they will have gone to other places," said Mr Little.
"We did not accept (the donations) and it simply beggars belief that they wouldn't have approached other political parties then and since."
Mr Little said Labour had rejected other donations as well, for example from the gambling industry.
Meanwhile, Mr Little said it was possible that money brought into New Zealand by former Chinese officials had been invested, or laundered, through the residential property market.
Prime Minister John Key said he had no information about that.
"Yeah look I wouldn't want to speculate on what they do with those funds, they could do a variety of different things and be held in a variety of different places.
"The issue that was raised with me wasn't where the money's going, just that there's concern there could be people in New Zealand who had essentially bought funds with them that were illegally obtained."
Mr Key says if New Zealand did send officials suspected of corruption back to China, it wouldn't want a cut of of any money they are accused of taking, as has been suggested in the Chinese media.