More than 200 Australian police are to be deployed in the troubled nation of Papua New Guinea, after the two countries signed an agreement on Thursday.
The move is part of a new Australian policy to take a more interventionist approach to the problems of its small island neighbours.
Australia is also leading a regional force of more than 2,000 troops to restore order in the Solomon Islands.
The Australian foreign minister, Alexander Downer, and the prime minister of Papua New Guinea, Michael Somare, signed the agreement in the Papua New Guinea capital of Port Moresby.
Mr Downer said an estimated 200 members of the Australian Federal Police would be deployed "as soon as possible", most likely by January.
Australia will also send officials to work in key positions to improve public administration.
The deal follows weeks of heated exchanges between the two countries, after Australian Prime Minister John Howard said he wanted a bigger say in how
aid money was spent.
Papua New Guinea is Australia's biggest aid recipient, receiving A$330m ( US$220 million ) every year.
Mr Somare initially rejected the Australian proposals, saying Papuans would decide for themselves "what type of people we would have to help us out."
But at a news conference on Thursday, Mr Downer said: "When you help people, you're not interfering."
"It does not represent an era where Australia is becoming more aggressive or post-colonialist, it represents an era of heightened Australian engagement," he said.
Papua New Guinea is one of more than a dozen near-bankrupt island nations affected by Australia's demands for greater aid accountability.
Earlier this year, a report described the country as being on the brink of anarchy, with falling living standards, entrenched corruption and mismanagement.
The US-led war on terror has heightened Australia's concerns over its troubled island neighbours.
Mr Howard has previously warned that failing states in the region could become a haven for terrorists.