Australian Alek Sigley has been freed from detention in North Korea more than a week after he was reported missing, landing safely in China after Swedish officials helped to secure his release.

Key points: Mr Morrison said Mr Sigley had been released but did not detail the circumstances of his detention

Mr Morrison said Mr Sigley had been released but did not detail the circumstances of his detention His release was secured thanks to the "discreet behind-the-scenes work" of Swedish officials, Mr Morrison said

His release was secured thanks to the "discreet behind-the-scenes work" of Swedish officials, Mr Morrison said The 29-year-old was reported missing by friends last week

Mr Sigley arrived in Beijing on Thursday, telling reporters he was feeling "great", but declining to answer any questions about his time in the Democratic People's Republic of Korea (DPRK).

"I'm fine. I'm very good," he said.

He was accompanied by Swedish Government envoy Kent Rolf Magnus Harstedt, and was ushered out of the airport by an embassy vehicle shortly after.

He then flew on to Japan, where he again declined to speak to the media as he strolled through Tokyo's Haneda airport just after 10:00pm.

Escorted by the Australian embassy's consul-general, Mr Sigley went through immigration — and out a special exit away from more waiting media.

Australian Prime Minister Scott Morrison announced the release of Mr Sigley in Question Time on Thursday.

"Alek is safe and well," Mr Morrison said.

"We were advised that the DPRK have released him from detention and he has safely left the country and I can confirm that he has arrived safely [in China]."

Australia's limited diplomatic presence in North Korea meant officials had to go through the Swedish Government, which has an embassy in North Korea, to provide consular assistance to Mr Sigley.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 59 seconds 59 s Mr Sigley's release was announced by Mr Morrison during Question Time.

"On behalf of the Australian Government I would like to extend my deepest gratitude to the Swedish authorities for their invaluable assistance in securing Alek's prompt release, which demonstrates the value of discreet behind-the-scenes work by officials in solving sensitive consular cases in close partnership with other governments," Mr Morrison said.

"I'm sure we all could not be more pleased."

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 15 seconds 15 s Alek Sigley touches down in Japan after release from North Korean detention

In 'good spirits' in Beijing

The 29-year-old's father, Gary Sigley, said he was very happy to hear his son was safe.

"I just spoke to Alek and he's in good spirits and he's looking forward to seeing his wife as soon as possible," he told the ABC.

"He's well, he's physically and mentally fine."

Asked whether he knew what had happened to his son while he was detained, Mr Sigley said: "I know nothing, any more, about the situation."

"I suppose at some point he'll come back to Australia, but we're just in the initial stage of being so relieved that everything's worked out well," he said.

"We're just so happy now that that situation has been resolved and that we know he's safe and sound in Beijing and in the care of the Australian Embassy, and I am sure they will treat him very well."

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 1 minute 46 seconds 1 m 46 s Mr Sigley's father, Gary, thanked the "the silent heroes" who secured his son's release.

Foreign Affairs Minister Marise Payne said Swedish diplomats met with North Korean officials on Australia's behalf on Wednesday to discuss Mr Sigley's disappearance.

"We received advice overnight that the detention was in place," she told 2GB.

"Then, later in the morning, the Swedish ambassador in South Korea was kind enough to advise our post in Seoul that there was a strong possibility that Alek may be able to be handed over to their Swedish delegation at the airport, as they were leaving the DPRK."

"So really the timeline was very tight and very short and without support and help of our counterparts in the Swedish Government, this would not have been possible.

"So we are deeply, deeply grateful to them."

North Korea not dangerous, Sigley said

Mr Sigley was reported missing by friends last week.

The 29-year-old, who was believed to be the only Australian living in North Korea, began studying for a master's degree in Korean literature at Kim Il-sung University in Pyongyang last year.

Mr Sigley married his Japanese-born wife Yuka Morinaga last year in Pyongyang. ( Facebook: Alek Sigley )

He is the founder of Tongil Tours, an Australian-based company specialising in guided tours to North Korea since 2013.

In 2017 he told the ABC North Korea was "a fascinating country, there's no other country in the world like North Korea" and said it was not dangerous to travel there.

"If we thought it was unsafe, we'd stop doing these tours," he said at the time.

Mr Sigley grew up in Perth but attended the Australian National University in Canberra before moving overseas.

Mr Sigley did not answer questions about his time in North Korea. ( AP )

ABC/AP