China's ambassador to Australia has played a graphic propaganda video titled Fighting Terrorism in Xinjiang while dismissing concerns about the mass detention of Muslim Uyghurs in his country as "fake news".

Key points: Ambassador Cheng Jingye held a rare public press conference with Australian journalists

Ambassador Cheng Jingye held a rare public press conference with Australian journalists He claimed there had been no mass detention of Uyghurs

He claimed there had been no mass detention of Uyghurs But Mr Cheng confirmed an Australian academic remained detained without charge

In a rare public appearance, Cheng Jingye fielded questions for more than an hour from Australian and Chinese-language reporters in Canberra, promising to "do more" to ease the strained relationship between both nations.

Speaking inside his official residence, Mr Cheng insisted that an Australian writer held for months without charge in Beijing was in "good condition" and suggested Prime Minister Scott Morrison could soon be invited to visit the Chinese capital.

Chinese-Australian writer Yang Hengjun has been detained without charge in Beijing since January, while two Australian politicians have been banned from entering China.

"The relevant Chinese security department will deal with the case in accordance with Chinese law and his lawful rights are protected," Mr Cheng said.

"In due time you will know the details."

The diplomat also repeatedly denied China was holding over 1 million Uyghurs in detention camps, explaining they were instead receiving "vocational training".

Uyghur men and women sit in a classroom during a Chinese Government-organised tour of Kashgar in Xinjiang. ( Reuters: Ben Blanchard )

As he justified Beijing's actions, the ambassador played a Chinese propaganda video that portrayed the ethnic minority as violent extremists.

Australia has been a vocal critic of China's mass detention of Uyghurs and other Muslim minorities.

The United Nations says at least 1 million ethnic Uyghurs and other Muslims had been detained in vast indoctrination camps.

A leaked 400-page document released by the New York Times last month revealed the key role played by top Chinese officials, as well as President Xi Jinping, in the establishment of the camps.

Map of Xinjiang province ( ABC News: Alex Palmer )

Mr Cheng described 2019 as "a mixed year for bilateral relations" that "could have been better".

"We expect that this relationship will be back to normal with the efforts of both sides," he said.

Despite the diplomatic tensions, the Chinese ambassador did not rule out Mr Morrison being invited to Beijing.

"There are efforts between the two sides, there will be more high-level exchanges and visits," he said.

"As ambassador, of course, I will do what I can ... to promote these relations, these important relations."

The ambassador also claimed that a 33 per cent increase in Australian exports to China was "largely responsible" for the federal budget being restored to surplus.