'I'm good': Australian student Alek Sigley released from North Korea

The Australian student who went missing in North Korea has left the country and is now "safe and sound" in China, according to media reports.

Alek Sigley, 29, was reportedly arrested at a university in North Korea just over a week ago, months after writing about being the only Australian in the country.

Sigley, who has been studying at Kim Il Sung University in Pyongyang, is originally from Perth, Western Australia, and has been heavily profiled about life in the notoriously secretive country by several media organisations, including Sky News, The Guardian and Public International Radio (PRI).

The NK News reports that Sigley, who has not been heard from for more than a week, is now "safe and sound" in China.

He is expected to travel to Tokyo soon, to join his wife Yuka Morinaga, who lives there.

The Aussie student was all smiles as he made his way through Beijing Airport.

"I'm OK, I'm OK. I'm good … I'm very good," told reporters as he pushed his luggage through the airport.

He said he felt "great".

His smile faltered for a moment when one of the reporters asked what happened in North Korea.

He is now reportedly at the Australian Embassy in Beijing.

There were fears Sigley had been detained by North Korean authorities.

The Prime Minister extended his "deepest gratitude" to the Swedish authorities for helping Alek get released.

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

"We couldn't be more pleased that we not only know where Alek is, but that he is safe."

Mr Sigley's father spoke to reporters in Perth and confirmed that his son was in Beijing.

"We're very happy he is safe and sound," he told the press.

He also thanked the Department of Foreign Affairs and Trade (DFAT) and "all those working in the background who helped bring this about".

Foreign Affairs Minister Marise Payne told the Senate that Mr Sigley's family has expressed its relief and gratitude.

Senator Payne said she had spoken to his father and described him as being "enormously relieved".

The family "has asked that we convey the thanks to everyone who has helped and expressed support for them over the past several days", she said.

The 29-year-old had been studying a postgraduate degree at Kim Il Sung University in Pyongyang and worked as a self-employed tour company operator at Tongil Tours.

- With news.com.au