Immigration Minister Peter Dutton expects more refugees on Nauru to sign up for resettlement in Cambodia after the first group touched down in Phnom Penh.
The refugees - three Iranians and one ethnic Rohingya from Myanmar (Burma) - arrived at the capital's airport on Thursday after being held in custody in Darwin for several weeks.
The airport's chief immigration officer Chhay Bonna said they had been handed over to the International Organisation for Migration.
Journalists were barred from entering the airport's VIP terminal, where officials from the Australian embassy and the IOM waited for the group to land.
The IOM told AAP the group will be housed in temporary accommodation for up to a few months before transitioning into the community.
They will have access to intensive Khmer language classes, cultural orientation lessons, trauma counselling and assistance to find work, study or start a business.
Mr Dutton is confident it will be a success.
"I think we can demonstrate it can work for these four and others can follow," Mr Dutton told Sky News on Thursday.
He hit back at criticism from human rights groups over the deal and Cambodia's poor humanitarian record, saying Australia was satisfied by the undertakings of government officials in Phnom Penh because they were "people of their word".
Amnesty International seized on the findings of its new report to express concerns for the safety of the four.
The report details the Cambodian government's violent repression of some of the largest demonstrations in the country's history during the disputed 2013 election.
"Our report documents how victims of serious human rights violations by security forces have been left without justice and effective remedies, while those responsible continue to walk free," Amnesty's research director for Southeast Asia Rupert Abbott said in a statement.
The findings bolstered concerns that refugees transferred to Cambodia may not be protected from human rights abuses, he said.
Australia offered Cambodia $40 million over four years to be spent on landmine eradication projects, rice milling and electoral reform initiatives in exchange for accepting refugees.
Australia will also pick up the tab on refugees' resettlement expenses, with $15.5 million allocated so far.
ABOUT THE CAMBODIA RESETTLEMENT DEAL
* Cost of refugee resettlement - $15.5 million
* $40 million foreign aid sweetener for Cambodia
* Refugees will only be sent on a voluntary basis
* Cambodia to decide numbers
* Cambodia continues to rebuild forty years on from the Khmer Rouge genocide
* Poverty, corruption, human rights abuses and unemployment are big problems in Cambodia
