Andrew Chan and Myuran Sukumaran, ringleaders of the  "Bali Nine" drug smuggling gang, lost a legal bid in the Balinese capital Denpasar to have their cases reviewed on Wednesday, dashing their final hope of avoiding the firing squad.
They were arrested in 2005 and sentenced to death the following year for attempting to smuggle heroin out of Indonesia.
Abbott said  his government had "left no stone unturned" in the bid to save them.
"We oppose the death penalty, we do whatever we humanly can to try to ensure that no Australian suffers the death penalty," he told reporters.
"We are not going to engage in last-minute, megaphone diplomacy but I just want to assure people that the Australian government has left no stone unturned to try to ensure that these two Australians on death row have their sentences commuted."
Chan and Sukumaran's lawyers based their argument for a reprieve on past legal errors, and said the pair had been rehabilitated and this should be considered.
The pair's Australian lawyer Julian McMahon said he would work to continue their legal fight despite the setback.
"The basis of the application actually was that there was error of law so what we're looking at now are the legal options that flow from that but there's no doubt the situation is bleak," he said.


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