Winston Peters has called for an inquiry over revelations a National Party MP has links to the Chinese military.
A bluegrass band warmed-up a crowd of about 200 people in Dunedin before Peters spoke at a public meeting there on Thursday, but it was the New Zealand First leader who had the audience singing from his song sheet.
Peters accused the National Party of making the country vulnerable by recruiting list MP Jian Yang, saying his links with the Chinese military "has only now been opened up, but not yet laid bare".
In the wake of allegations that he studied at an elite Chinese spy school, Dr Yang revealed on Wednesday that he had a background as a civilian, or non-ranking, officer in the Chinese military, and had previously taught English to students in China so they could monitor communications and collect information.
But Yang rejected any suggestion he was trained by Chinese spies, or was once a spy himself, calling such allegations a "smear campaign by nameless people". He said he had always been upfront with National about his background.
It was common for Chinese people living in New Zealand to have some form of military background, Yang said on Wednesday.
"I can understand [how] people can be concerned because they don't understand the Chinese system. But once they understand the system they should be assured this is nothing, really, to be concerned about."
Peters said he had previously raised concerns about Yang in Parliament, in April and again in July, when he attacked a speech by the National Party MP as being "straight out of Beijing".
He told media after his speech that when he voiced his concerns he was "immediately accused of being racist".
Yang should step aside to allow for a full inquiry into his background as there must be proof he was "not a risk", he said.
The issue of Yang was a concern for the economy and Government decision-making, as well as being bad for "our allies because we look like a country that is so naive we can't be trusted".
Prime Minister Bill English and the National Party needed to "seriously explain themselves," over the issue, Peters said.
He also used the opportunity to lash out at Chinese ownership in New Zealand, including Silver Fern Farms, which has its headquarters in Dunedin.
Peters said Chinese interests were "starting to dominate the lives of New Zealanders and clearly our economic direction".
Those moves were "just appalling" with "large chunks of our economy subverted by the Chinese," he said.
A National Party spokesman declined to comment on Peters' call for an inquiry.