Australian officials are doing what they can to secure the release of five Australians held in West Papua since last September, Prime Minister Kevin Rudd says.

Consular staff had provided extensive assistance to the five since shortly after their detention, he said.

"They have maintained a continuous presence in that part of Papua since September 2008 until January 2009 after which... (they) made frequent visits to the area to check on their welfare," Mr Rudd told Fairfax Radio Network on Friday. The next visit is due in June.

Australia was working with Indonesian authorities on what Mr Rudd described as a complex case.

The five – pilot William Scott-Bloxam, his wife Vera, and passengers Keith Mortimer, Hubert Hofer and Karen Burke – say they visited West Papua on September 12 last year to investigate tourism opportunities. They were arrested after landing and charged with immigration offences.

The five were jailed for two to three years, then freed on appeal, but a travel ban was placed on them by Indonesia's attorney-general until prosecutors could appeal to the Supreme Court.