The pilot, named as David John Cutmore by PNG newspaper The National, is being interviewed by Australian Federal Police in the PNG capital after Sunday's crash.

Prime Minister James Marape earlier this week said PNG police believed drug trafficking may be behind the clandestine flight.

The flight out of Mareeba airport in far north Queensland ended near a recently cleared bush airstrip 30km west of Port Moresby, with the twin-engined Cessna 402C written off.

PNG Acting Chief Migration Officer Robert Kennedy told The National Mr Cutmore had been charged with illegal entry under the country's Migration Act.

"Police are now conducting a separate investigation on him which may involve illegal activities," Mr Kennedy said, adding that Mr Cutmore was not carrying a passport.

PNG police were notified on Tuesday Mr Cutmore had turned himself in at the Australian High Commission.

In a statement on Thursday, the AFP said it was working with PNG police to "investigate the circumstances around the crash" and those investigations were ongoing.

Commenting on the incident earlier this week Mr Marape said PNG was "not a banana republic" where people could just fly in unannounced.

"There is no room for those who think they could peddle drugs in PNG," he said.

Australia's Department of Foreign Affairs and Trade has told AAP it was providing consular assistance "to an Australian man in Papua New Guinea".

"Owing to our privacy obligations, we will not provide further comment."

An aircraft register search shows the plane's owner as of January this year was Ravenpol No. 69, based in Port Moresby, while the operator was named as Alice Springs-based aviation company Avlease.

But Avlease director Ian Scheyer told the ABC his company had never operated the plane and was shocked it was listed on Australia's Civil Aviation Safety Authority's register.

Australian Associated Press