Australian student Alek Sigley says he is feeling great after being freed from detention in North Korea, but remained tight-lipped about his experience.

The 29-year-old arrived in Beijing on Thursday and will fly to Tokyo to reunite with his wife.

"I'm OK, I'm OK, yeah. I'm good. I'm very good ... great," he told reporters at Beijing airport.

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

He was accompanied at the airport by Swedish diplomatic officials who negotiated with North Korea on Australia's behalf to secure his release.

Mr Sigley was taken from the airport to the Australian embassy in Beijing.

His relieved father Gary Sigley was hopeful of learning more about his son's detention shortly.

"I am sure in the coming days and weeks there will be some more information about what has transpired," he told reporters in Perth.

In a Thursday night press conference, Prime Minister Scott Morrison said Mr Sigley's departure to Japan was imminent.

"I cannot imagine how wonderful it will be for them to be reunited," he told reporters in Canberra.

Mr Morrison expects to speak with Swedish Prime Minister Stefan Lofven later on Thursday night to thank him.

But the prime minister refused to elaborate on the reason for Mr Sigley's detention in the hermit kingdom.

"It is in nobody's interests in these quite sensitive consular cases, to go beyond simply saying, I'm so pleased that he is safe and I'm so pleased he's been reunited with his family," Mr Morrison said.

Swedish Foreign Minister Margot Wallstrom said she was relieved the situation was resolved.

"Happy for the release of Australian citizen Alek Sigley today!" she tweeted.

"Sweden has done its utmost to work for Mr Sigley under our bilateral agreement with Australia."

Australia does not have an embassy in North Korea, so asked Sweden's delegates in Pyongyang to meet with North Korean officials on Wednesday to raise Mr Sigley's disappearance.

The Perth man was then released on Thursday morning.

Mr Sigley, who runs the Tongil Tours tour company and had been studying in Pyongyang, was detained in North Korea last week.

He was last heard from on June 25 and had since fallen silent on social media.

His father Gary Sigley said the family is "over the moon" that Alek is safe.

"He is fine, he is in very good spirits, he's been treated well," he told reporters at home in Perth.

He said he hoped to see his son in Australia soon but did not know whether he would return to North Korea.

"At this stage I have no idea what is travel plans are," he said.

He admitted the family had been anxious since Alek's disappearance.

"The last week has been a very difficult week for Alek's immediate family, we were very worried when we didn't have any news about his situation," he said.

"We are just so happy now that the situation has been resolved and we know he is safe and sound in Beijing and in the care of the Australian Embassy.

"It is also good to know that he has been in constant good spirits and been well the whole time."

He thanked the Australian and Swedish governments for their "stellar work."

"And also those working in the background, the silent heroes who helped bring this about."

Mr Sigley grew up in Perth with his father, an Asian Studies academic, and his Chinese-born mother.

He studied at the ANU in Canberra and then in Beijing, Shanghai and Seoul and is fluent in Mandarin and Korean, as well as speaking some Japanese.

He started a Masters degree in Korean literature at Kim Il Sung University in Pyongyang in 2018 after first visiting North Korea in 2012.

Mr Sigley's is the first known arrest of a foreigner in North Korea since American student Otto Warmbier, who was sentenced to 15 years hard labour for allegedly stealing a propaganda poster in 2015.

Mr Warmbier was repatriated to the US in a coma a year-and-a-half later, and died six days after his return.