Australia's Prime Minister Kevin Rudd says his country's officials are doing what they can to secure the release of five North Queenslanders held in Indonesia's Papua province since last September.
In March, Indonesian prosecutors lodged objections to a High Court decision to free the so-called Merauke Five who illegally flew their plane to the Papuan town of Merauke last September.
Earlier this year, the High Court overturned a lower court's three-year sentence against pilot William Scott-Bloxam and the two-year sentences given to his four passengers.
However, prosecutors claim this was an incorrect reading of the law and they are still pursuing the case.
Canberra has been criticised by supporters of the group for not having secured the release of the five Australians, who are all over 50.
But Mr Rudd says consular staff have provided extensive assistance to the five since shortly after their detention.
He says Australia is working with Indonesian authorities on what he describes as a complex case.