Prime Minister Tony Abbott is prepared to give Opposition Leader Bill Shorten some credit for wanting to adopt his government's boat turn back policy.
"I'm prepared to say: good on Bill," Mr Abbott told ABC television on Thursday.
But the applause came with a swipe, as the prime minister told Labor that had the party implemented the policy in government hundreds of lives could have been saved.
"I just wish he'd done it when he was in government because ... up to 1000 people might not be dead," he said.
Mr Shorten now supports turning back asylum seeker boats, saying it must be an option should Labor be elected into government.
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He conceded the coalition's mix of policies was defeating people smugglers.
The move has angered the Labor Left faction but its understood Mr Shorten has enough support to retain the policy option.
Mr Abbott also questioned Labor's sincerity on turnbacks, a concern aired earlier by Immigration Minister Peter Dutton.
"If I thought it was genuine, I would welcome it," Mr Dutton said.
Treasurer Joe Hockey was also sceptical, saying it had all the hallmarks of a pretend fight.
Prominent Labor backbencher Anna Burke is bitterly disappointed with the Shorten plan, which could be debated at the ALP national conference, which starts on Friday.
"(Former Liberal prime minister John) Howard created political footballs out of human lives and we have to get above that," she said.
The Greens have accused Mr Shorten of "kowtowing" to the government's policy of turning back asylum seeker boats.
