The Australian government says there is still no word on the whereabouts of an Australian student missing in North Korea for several days.

The country's Prime Minister Scott Morrison, who is currently in Osaka for the G20 summit held an interview with Australian media on Friday and said his government does not have any further information, simply saying the issue is very concerning.

The family of Alek Sigley, the 29-year-old graduate student at a North Korean university suspected to have been apprehended sometime earlier this week, said earlier Thursday they had not heard from him since Tuesday.

Morrison said Australia has as of yet been unable to establish what has happened to Sigley. Canberra has no diplomatic presence in North Korea and relies on third-party countries such as Sweden to act on its behalf.

Leonid Petrov, a North Korea expert at Australian National University who knows Sigley, has speculated that ahead of a possible third summit with the United States, the Kim regime may have taken steps to cut off the Perth native from communication channels.

Sigley, studying at the North's Kim Il-sung University since early last year, was until Tuesday widely active on social and conventional media, where he documented and wrote about his experiences in the communist state.