The Federal Government has revealed that 12 asylum seeker boats have been turned back at sea since its border protection policy was implemented.

Immigration Minister Scott Morrison today used the first anniversary of the launch of Operation Sovereign Borders to make public the details of on-water operations that have until now largely been kept secret.

A factsheet released by his office has revealed that 383 asylum seekers on 12 boats were turned back from Australian waters.

The first was turned back on December 19 and the most recent was on May 20.

Four of those turnbacks involved sending asylum seekers back to Indonesia in orange lifeboats.

"We ensured that when we put the turnback operations in place that we knew we could do that safely, effectively and sustainably, and the ability to do that has been the critical blow to people smugglers," Mr Morrison told AM.

The minister says the lifeboats have proven to be a safe option.

"We have not lost a single life at sea under these operations because they've been done safely," he said.

"It is safety that drove the innovation of the policy that involved the use of lifeboats."

A separate operation involving authorities in Indonesia, Sri Lanka and Malaysia has stopped a further 45 boats that were bound for Australia.

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Since the Coalition was elected, 23 boats carrying about 1,200 asylum seekers have arrived in Australia, but all bar one of those arrived before December when authorities started turning boats around.

Mr Morrison's frontbench colleague and former Liberal leader Malcolm Turnbull acknowledged that many of the asylum seekers would have had plausible claims for refugee status had they reached Australia.

"I'm sure that many of the people in the boats that have been turned back would have plausible claims for refugee status," Mr Turnbull told Radio National.

"But the fact is, we've got to have a policy that works, we've got to stop the people smuggling. Yes, it is a tough policy."

Labor has questioned why the information was being released, considering how secretive the Government's policy has been.

Opposition immigration spokesman Richard Marles also claimed the turning point was Labor's introduction of a policy to resettle all asylum seekers offshore - a policy immediately adopted by the Coalition.

"What we saw from July 19 last year when Labor introduced regional resettlement arrangements with PNG was within a couple of months, a reduction in the flow of asylum seeker boats by 90 per cent," he said.

Though Mr Marles conceded that "the policy of turnbacks obviously has had an effect".

The Greens declared the anniversary of Operation Sovereign Borders marked a year of "cruelty".

"Turning back genuine refugees and forcing them to face danger in their war-torn homelands does not save lives no matter how hard the Government tries to spin it," Senator Sarah Hanson-Young said in a statement.

But Mr Morrison rejected the criticism, saying he was "dealing with the problem" of boat arrivals.

The policy has faced international scrutiny, with the United Nations asking the Government earlier this year to prove it was not breaching the Refugee Convention.