Simon Bridges' controversial China visit was organised by Jian Yang, the National MP who admitted to training Chinese spies, official emails show.

Bridges was criticised for praising the Chinese Communist Party (CCP) in an interview on Chinese state television during the five-day trip in September.

He also came under scrutiny for meeting the person in charge of the country's secret police, at a time when the CCP was detaining more than a million Uighur Muslims.

Under the pretext of countering terrorism and religious extremism, China holds Uighur Muslim children at 're-education' camps.

Correspondence released by the Ministry of Foreign Affairs and Trade (MFAT) under the Official Information Act showed National MP Jian Yang put together the trip's itinerary.

READ MORE:

* Bridges opens up foreign policy divide on China

* Blessings in India a special part of this trip, says National leader Simon Bridges

* Chinese businessman Yikun Zhang's donations go beyond Simon Bridges

Yang came under intense scrutiny shortly before the 2017 election when it was revealed he taught English at an elite Chinese spy school before emigrating to New Zealand.

Yang also studied at another military intelligence facility where Xu Meihong, a famous Chinese spy, was his classmate, according to the Financial Times. All up, he worked in Chinese military intelligence for 15 years.

In late August, Yang emailed National Party staff with the itinerary he put together for Bridges and said: "I'm rather pleased with it".

KEVIN STENT/STUFF In 2017 it was revealed Jian Yang had taught English at a Chinese spy school before emigrating to New Zealand.

A member of the Chinese Communist Party's 25-man Politburo would meet the delegation "although we do not know who that person is", Yang said in the email.

That person turned out to be Guo Shengkun, the head of the CCP's secret police.

Bridges' visit drew international attention from China watchers and journalists.

The Asia editor of the Financial Times, Jamil Anderlini, tweeted: "Why is the leader of New Zealand's biggest opposition party meeting with the head of China's secret police? And why is he in Beijing with a New Zealand member of parliament who spent 15 years working for Chinese military intelligence?"

David Capie, director of Victoria University's Centre for Strategic Studies, called Bridges' comments in his state media interview "truly extraordinary".

"Alarming to have such a big gap between government and opposition views/language concerning such a critical relationship," Capie said.

Yang and Bridges also arranged to travel together in the same car between events on their programme, emails show. Gerry Brownlee, National's spokesperson for GCSB, NZSIS and foreign affairs, was also on the trip.

In late August, nine days before Bridges and Brownlee were due to touch down in China, they hadn't asked for any assistance from MFAT.

SIMON O'CONNOR/STUFF National's spokesperson for GCSB, NZSIS and foreign affairs, Gerry Brownlee, also went to China.

"I've asked for copies of [Bridges'] programmes; offered in person briefings by senior MFAT officials; and indicated the extent of assistance MFAT can provide three times now," an MFAT staff member wrote to other staff.

"I'm not inclined to offer again, but perhaps we will see a last minute scramble of requests."

A colleague responded: "I agree you have done more than enough in terms of making it clear we stand ready to assist."

The following day, an MFAT staffer emailed David Hope, an MFAT official based in Beijing, and Andrew Robinson, New Zealand's Consul-General to Shanghai, saying they had the green light to "co-organise" the trip.

Yang then emailed his itinerary to National staff and it was forwarded to Hope and Robinson.

National announced in August that Yang would accompany Bridges and Brownlee to China, but the party never revealed Yang was organising the trip.

Bridges did not respond to a request for comment.