The Supreme Court in Papua New Guinea has ruled that immunity provisions granted to Australians serving under the Enhanced Co-operation Programme are inconsistent with the country's constitution.
More than 150 Australian police have been serving in PNG since late last year under the programme.
The Morobe Governor, Luther Wenge, challenged the programme, saying it was a threat to PNG's sovereignty.
Mr Wenge says the decision vindicates his earlier concern and is also a blow to the government's credibility.
"I told the parliament, listen this is illegal so go and talk it over. Unfortunately they pushed it through Parliament without much debate and they took advantage of their numerical strength, the numbers they have in Parliament to pass the law."
Mr Wenge says he doesn't necessarily want the Australians to leave PNG but both sides must come to the table and talk.
The president of the PNG police association, Robert Ali, says the judges have seen the need to rework the Programme.
We have a long-standing relationship with the Australians. But what we're saying is the manner in which the current arrangement with the ECP is being arranged, may not be going down well with our members, and of course, we've provided a forum, and you know, the members have already aired their views, and we're saying there's still some things wrong with the arrangement. So we have to take it back to the drawing board.
The president of the PNG police association, Robert Ali.
Australia has taken its assistance police in Port Moresby, off duty.
There are reports that police are on notice for departure this afternoon.
But a worker at the air traffic control tower at Jackson international airport in Port Moresby says she's not aware of any flight carrying Australian police that's scheduled to leave this afternoon.
A member of the Australian Federal Police in Port Moresby, Inspector Geoff Newby, said he was not at liberty to comment.
