Deputy Prime Minister Winston Peters has called for MP Jian Yang to be investigated over claims he intervened in a national security vetting case and didn't properly disclose his background with Chinese military intelligence.

This morning the Herald broke news that Yang, a National Party MP, had lobbied ministers in 2012 in a bid to overcome a block by the Security Intelligence Service on an job applicant seeking a sensitive job in the defence force.

Yang said a statement the job applicant was a constituent and denied lobbying. "I had simply sought answers on the constituent's behalf through the appropriate channels, as is the responsibility of every Member of Parliament,"

But Peters, also the foreign minister and leader of the New Zealand First party, today commended the report.


"The Herald's got onto something, and done their homework and done it right," he said.

He said he had never heard of a Member of Parliament seeking to involve themselves in vetting decisions and demanded answers.

"These are serious allegations that need to be investigated," he said.

Yang has become a lightning rod for domestic and international debate about China's increasing influence after the Financial Times and Newsroom revealed his background prior to becoming a New Zealand citizen and MP included at least 15 years working with China's military Intelligence apparatus.

National Party leader Bill English said he had not discussed today's Herald report with Yang, but defended his MP's handling of the episode.

"He's dealt with a concern from a constituent in a way that any MP is virtually obliged to. I think it's overstretching it to say that he tried to overturn a security classification," he said.

Prime Minister Jacinda Ardern declined to comment on individual national security cases, but backed comments last night from minister for intelligence services Andrew Little.

"As a general statement, it's inappropriate for MPs to lobby around security clearances," she said.