"Given that Nauru has signed the refugee convention and Malaysia has not why is the Prime Minister persisting with a policy that has been rejected by the High Court and many in her own party and offends every principle that she has ever espoused?" Abbott said.
Gillard's planned amendments are tailored to Abbott's earlier promises of bipartisan support for a solution allowing offshore processing, given after the High Court ruled three weeks ago that the deal to swap 800 asylum seekers for 4000 UN-accredited refugees from Malaysia was invalid.
Legal advice said the ban also extended to Nauru and the other former Pacific solution centre on PNG's Manus Island.
Gillard's proposed amendments would sidestep the ruling and focus on the broad power of the executive to make decisions rather than specifically address Malaysia.
This would also apply to any future Coalition governments, ensuring they could implement whatever policies they chose, including options rejected by Labor.
Gillard said the amendments were "not about Malaysia", but would enable the government of the day to design and implement its best solution, including a return to the Pacific solution.
"We are talking about bipartisanship to pass legislation which enables executive government to put into place its policy," she said.
"I am not asking Mr Abbott to agree with us on Malaysia. He can criticise Malaysia up hill and down dale, and I will maintain my objection to Nauru.
"This is something else. This is about Government having the power to act. We will seek the power to act."
Gillard said the Malaysian agreement would help smash "evil" people smugglers and provide the maximum deterrent to asylum seekers risking death at sea.
She said Nauru was not a deterrent, as 95 per cent of the asylum seekers processed there under the Pacific solution were eventually settled in Australia - and people smugglers had got the message.
"Malaysia says, 'you will not get to Australia'; Nauru says, 'here's a ticket to Australia'."
Immigration Minister Chris Bowen said the amendments had been tested by federal and eminent private legal experts to ensure they were as robust as possible, and the Opposition would be briefed on the wording this week.
Meanwhile, a Nielsen poll in Fairfax newspapers yesterday brought more bad news for Gillard, finding that former leader Kevin Rudd not only outpolled her as preferred Labor leader, but that the Government would return to an election-winning lead if Rudd returned to the top job.