AUSTRALIAN maritime workers warned today that a Bill giving ministers the power to secretly turn back vessels carrying immigrants was a "diversion and distraction for short-term political gain."

Right-wing PM Tony Abbott's maritime migration Bill - which would give the immigration minister power to secretly decide whether Australia's international obligations apply to any given ship - is currently before the senate.

Maritime Union of Australia (MAU) national secretary Paddy Crumlin said the Bill "allows Australian ships to secretly take people to any part of the world and exempts them from any other law in the process.

"Immigration Minister Scott Morrison has failed to grasp that these laws and conventions exist to save lives at sea, to protect fragile marine environments, and to ensure proper standards in shipping.

"Time and time again MUA members have been proud to be in the front line of search and rescue, including for asylum-seekers fleeing desperate circumstances, and to bring them to a safe port and landing.

"But this Bill undermines maritime workers' ability to offer that helping hand by removing a layer of
accountability in a dangerous, unpredictable industry."