'I'm OK': Australian student speaks after detention in North Korea

Perth student Alek Sigley has emerged from a week's detention in North Korea in good health and spirits as Australian authorities continue to probe the circumstances of his mysterious capture by the hermit regime.

The 29-year-old was studying in North Korea and disappeared last month. Friends and family became alarmed when he stopped responding on social media and other channels.

Australian student Alex Sigley arrives at the airport in Beijing on Thursday.Credit: AP

Mr Sigley was filmed walking through Beijing airport on Thursday, where he said: "I'm OK, I'm OK, yeah. I'm good. I'm very good ... I'm great."

But he only responded with "aah" when asked what happened in Pyongyang.

Mr Sigley, who also ran a tour company that took intrepid foreigners into North Korea on cultural and academic visits, was understood to be heading to Tokyo to be reunited with his Japanese-born wife.

There was little information as to the reasons for his detention, nor how Swedish diplomats who made representations to the North Korean regime on Australia's behalf managed to secure his release.

But Prime Minister Scott Morrison confirmed Mr Sigley had been held by the regime.

"Earlier this morning, we were advised the DPRK had released Alek from detention, and he has now safely left the country. I can confirm he has arrived safely," Mr Morrison said.

Mr Morrison sent Australia's "deepest gratitude" to Sweden for their help in securing Mr Sigley's release and confirmed that Mr Sigley was "safe and well".

"This outcome demonstrates the value of discreet, behind-the-scenes work of officials in resolving complex and sensitive consular cases in close partnership with other governments," Mr Morrison said.

Mr Sigley's father Gary said the family was "over the moon" that he was safe and well.

"We are very happy to hear that Alek is safe and sound now in Beijing and we would like to thank everybody, [the Department of Foreign Affairs and Trade], the Prime Minister, the Foreign Minister and Alek's close circle of friends and supporters who have been offering us support and helping out as best they can," he said.

Mr Morrison spoke to a wide range of other world leaders at the recent G20 summit in Japan about Mr Sigley's case.

Mr Sigley's former lecturer at the Australian National University, Leonid Petrov, who specialises in North Korea, said he had spoken to Gary Sigley and been told the family knew little at this stage about the circumstances of Mr Sigley's detention.

"It's good to see that Alek is in good health and spirits and is going to reunite with his wife," he said.

He said it was difficult to judge whether the meeting between US President Donald Trump and North Korean leader Kim Jong-un at the Korean demilitarised zone on the weekend had any bearing on Mr Sigley's detention.

"I would say that security precautions on North Korea were particularly high before that visit and obviously the news about the visit was circulating in North Korea because delegations were working together ... Whether that in any way affected the decision [to arrest] Alek is hard to say."

Foreign Minister Marise Payne said the Sigley family had "asked that we convey the thanks to everyone who has helped and expressed support for them over the past several days".

Australian student Alex Sigley walks through journalists as he arrives at the airport in BeijingCredit: AP

Opposition Leader Anthony Albanese joined Mr Morrison in welcoming the announcement.

"This is indeed good news for Alek, his family and indeed good news for our nation," Mr Albanese said.

Labor's foreign affairs spokeswoman, Penny Wong, added her thanks to Australian officials for their work.

with AAP