Despite three of the five refugees from Nauru having left Cambodia to return to the countries they once fled, Australian Immigration Minister Peter Dutton has pronounced his nation’s A$55 million resettlement deal with the Kingdom a “pretty good outcome”, even as critics labelled the scheme “all but over”.

Dutton’s efforts to defend the controversial scheme came after it emerged on Monday that an Iranian refugee couple, among the first four arrivals in June, had returned to Iran in February, four months after another from the first batch, believed to be a Rohingya man from Myanmar, also went home.

Responding to a suggestion that A$55 million made for an “expensive stopover”, Dutton told an interviewer from Australia’s Channel 9 that sticking with the deal would stop asylum seekers from travelling to Australia by boat and drowning at sea.

“I think that is a pretty good outcome,” Dutton said, after noting the bulk of the A$40 million given to Cambodia to take the unwanted refugees was aid money targeted toward local communities, election preparation and agriculture.

“We have been very clear about the fact if you come to Australia by boat, you will never settle here,” he said.

Signed in 2014, the deal, which also included A$15 million to cover resettlement costs, has drawn widespread condemnation, with critics accusing Australia of shirking its obligations to refugees.

But more embarrassingly for Australia is its failure to attract participants, despite offering cash incentives. Only two refugees from the program remain in Cambodia – a young Iranian man from the first group, and another Rohingya man from Myanmar who arrived in November.

More than 400 refugees and asylum seekers are currently held on Nauru.

Speaking via phone yesterday, a refugee who arrived on the Pacific island in 2013 after fleeing religious persecution in Pakistan said representatives of the Australian government regularly told those held there they had “no choice” but Cambodia.

But no one was interested, he said. “We travelled to Australia to start a new life we did not come to go to Cambodia,” the refugee, who requested anonymity, said, adding most of the group was holding out in the hope of resettlement in a developed country.

Quoted by AAP yesterday, immigration spokesman for the opposition Australia Labor Party Richard Marles declared the “botched” program “all but over”.

Via email yesterday, Sarah Hanson-Young, a senator for the Australian Greens Party, agreed. “The $55 million given to the Cambodian government to take only five refugees, three of whom have now left, has been a blatant waste of taxpayers’ money,” she said.

“For Minister Dutton to claim this is a ‘good outcome’ shows he has no regard for the well-being of these people or Australia’s reputation in the region.

“There are plenty of ways the Australian government could have used this money to meaningfully assist Cambodian people, instead of bribing the Hun Sen government to deal with our mess.”

Carl Thayer, an emeritus professor at the University of New South Wales, said the deal, made in desperation, had always been a “non-starter”, leaving Cambodia the big winners financially. “Cambodia was the price maker,” Thayer said, via phone. “Cambodia doesn’t lose. It’s offered to take them; the fact they don’t want to go there is another matter.”

With its Cambodia and Papua New Guinea resettlement programs flailing, Canberra is in discussions with several other countries – including Malaysia, the Philippines and Indonesia – to resettle refugees.

Dr Andrew Carr, of the Australian National University’s College of Asia & the Pacific, said regional resettlement had some merit but Canberra needed to use its experience with Cambodia as “a test” to learn how to make such a program attractive, sustainable and humane.

“If the government has been looking for a quick fix, as many fear, then it will have failed, but if it has been as a more serious, long-term alternative, then this really is just one stage in a much longer process,” he said.