An Australian think tank, the Centre for Independent Studies, says the Papua New Guinea political and bureaucratic elite helped force the Australian police from the country.
Around 120 police, in PNG as part of the Enhanced Co-operation Programme, or ECP, left two weeks ago after a court ruling that they didn't have immunity from PNG law.
The Centre's Professor Helen Hughes says the ECP is vital for the restoration of security which would allow the country to develop its economy and provide for its rapidly growing population.
But she says this tiny elite was threatened by the police presence.
Professor Hughes says most politicians and civil servants in PNG are corrupt.
"It's been documented in detail for example for the timber industry. The mainly Malaysian, Phillipines timber companies are getting leases to which they are not entitled. They're ripping out the timber and not replanting. They're exploiting local people and paying off officials and parliamentarians in order to do that."
Prior to the court decision, hundreds of local police had called for the Australians to leave and Professor Hughes says this was because the Australians were already having an impact.
Most police are very poorly paid and they make up their living by collaborating with the raskols and the gangs, and for example, the women who sell betel nut on the kerb have to pay protection money to the police. And if they don't pay protection money, police come along grab a fist of betel nut and throw the rest in the road. Only six months into the ECP and that was being stopped.