Winston Peters has "welcomed" the news that National MP Jian Yang is retiring from politics, describing the Chinese Communist Party (CCP)-linked politician's tenure in Parliament as "shameful".
Dr Yang said in a statement on Friday that after "careful consideration" and talking to his wife and children, he came to the decision not to stand at the September election as a list MP.
Peters, leader of New Zealand First, said with Dr Yang's retirement National "now has the opportunity to publicly commit to not take any more donations facilitated by individuals with links to the Chinese Communist Party".
Dr Yang made headlines across the globe after admitting in 2017 to training Chinese spies so they could monitor other countries' communications. But he denied ever being a spy and denied ever having intelligence training.
The 58-year-old MP came under fire recently after being criticised in a TVNZ report over refusing an interview with a Q&A journalist for more than two years.
"It is breathtaking, given New Zealand's long democratic tradition, that National has tolerated the intolerable by protecting Mr Yang from being held to account by our media," Peters said.
"He has never satisfactorily explained his past links with the CCP and their military intelligence-linked language schools, nor has he or the National Party ever apologised for his misleading statements when he applied for citizenship."
Dr Yang once taught at the People's Liberation Army-Air Force Engineering College, and spent time at the Luoyang Language Institute run by the Third Department, which carries out spying activities for Chinese intelligence.
It was later revealed Dr Yang did not disclose his links to the schools in his citizenship applications and instead described them as 'partner' universities which had a relationship with military institutions.
"This is shocking when you think about it," Peters said, "A low point in protecting some of New Zealand's most sensitive relationships."
National leader Todd Muller has defended Dr Yang, describing him on Friday as a "remarkable" and "very passionate" MP.
"He's decided, for his own family and professional reasons, to leave and move on to new adventures and we wish him well."
Muller also disputed that Dr Yang wasn't visible enough to the public.
"Every MP has their own degree of visibility. The critique in terms of not being available to the media was wrong. He'd made himself available a number of times in the last year in his role as statistics spokesperson."
Muller said politics can be a tough gig.
"Politics can be demanding. It can take its toll on people. He had signalled, as he has today, that he would like to - after reflection with his wife and family - move on. I deeply respect that and deeply respect the contribution he has made."
Peters criticised National for accepting "foreign donations whose origins have not yet fully emerged" and said National "saw, heard, and spoke no evil throughout the shameful period that Jian Yang was in Parliament".
National's ties to China came under scrutiny in 2018 when ex-National MP Jami-Lee Ross claimed a donation from Chinese businessman Zhang Yikun worth $100,000 was broken up into eight smaller sums so it didn't have to be declared.
Ross accused his former boss Simon Bridges of electoral fraud, but a Serious Fraud Office (SFO) investigation resulted in Ross facing charges along with Zhang Yikun and two other associates - not Bridges nor the National Party.
Ross pleaded not guilty and his case will be heard before a jury on September 6, 2021.
The SFO is also currently investigating the New Zealand First Foundation after the Electoral Commission said in February the New Zealand First Foundation "received donations which should have been treated as party donations".
The allegations were made in a Stuff report in November 2019, citing documents that purportedly showed undeclared financial exchanges between the New Zealand First Foundation and New Zealand First Party.
Peters described the claims as "filthy allegations without any proof".