National list MP Dr Jian Yang announced his retirement from politics and said he would not stand in the 2020 general election after three terms in the party caucus.

He said politics was "demanding" and he wanted to spend more time with his family.

"Accordingly, I have informed the party president that I should not be considered by the regional list ranking committee of the Northern Region in its meeting tomorrow, hence my announcement today.

"I truly believe that New Zealand is a great country."

Of the 21 years he has been in New Zealand, he has spent 12 years in academia and nine in politics.

"I have been proud to be a part of what I think is a caucus that is truly representative of the ethnic diversity that is modern New Zealand, and to have played my part as a Chinese New Zealander in the governance of our amazing country."

He said he was honoured to represent the Chinese community in Parliament.

"I am proud that I have been able to assist numerous Chinese constituents and enabled the Chinese community to better understand and participate in New Zealand's open and democratic politics. And I will continue to support New Zealand's hard-working Chinese community outside of caucus.

In 2017, Yang confirmed he had taught 'spies' in China, but denied that he was a spy himself. A story on the Newsroom website raised questions about his involvement with Chinese military and intelligence.

He was a member of the Communist Party while he was in China but hadn't been since he left the country, he had said.

He said he enjoyed being part of governments led by Sir John Key and Sir Bill English and to have chaired two select committees.

"My trips to China with Prime Minister John Key, Ministers and colleagues are some highlights of my political career. I have witnessed the rapid growth of New Zealand's trade with China and I am pleased to have played a role in it.

"I wish Todd and the team all the best to win the election. New Zealand needs a National government."

Last month National MP and ousted deputy leader Paula Bennett had also announced she would not be standing at the upcoming election.