A married Iranian couple who were once refugees at Nauru have left Cambodia and returned to their homeland despite the potential dangers, in a further sign Australia's $55 million deal with the south-east Asian nation has failed.
The office of Immigration Minister Peter Dutton confirmed the development on Tuesday, but said Nauru refugees were still encouraged to move to Cambodia.
It means Australia has paid Cambodia $55 million to permanently resettle just two refugees - striking a further blow to the much-maligned deal.
Australian Immigration Minister Peter Dutton with Sok Phal, director of the Cambodian Interior Ministry's immigration department last year. 
Labor's immigration spokesman Richard Marles said the deal had been "botched" and reflected the government's "abject failure" in dealing with asylum seekers.
"Not only has this government wasted $55 million of taxpayers money on this dud deal, they have also left more than 2000 people on Manus and Nauru in limbo for nearly three years on their watch," he said.
"The inability of this government to secure a meaningful resettlement arrangement with a credible third country is a serious failure on the part of Malcolm Turnbull."