In one policy, it states the navy should only help asylum seekers when its safe to do so. But another policy states the navy may only help vessels carrying asylum seekers when it is 12 nautical miles outside Indonesia's archipelagic baseline.

The committee found that for navy officers to ensure the safety of asylum seekers, there was an inherent risk of their vessels entering Indonesian waters, therefore breaching international law.

''The committee is concerned that the two policy directions may not be compatible in the challenging real-life situations in which vessel commanders find themselves under Operation Sovereign Borders,'' the report said.

Between December 1 and January 20 there were six incursions into Indonesian waters, the report found.

The incursions were reported to senior Australian officials on January 15, who passed information on to the Indonesian government the next day.

Indonesia responded by stepping up its naval presence monitoring its southern border.

The Australian government has since formally apologised to the Indonesian government for what it describes as an inadvertent mistake.

But the Greens immigration spokeswoman, Senator Sarah Hanson-Young, said the contradiction in the operation's policies made it ''unworkable''.

"Cutting a leaky wooden boat adrift more than 12 miles from a coastline that you can't see is inherently dangerous," Senator Hanson-Young said.

The committee also sought to discover the lines of inquiry in Operation Sovereign Borders, saying the secrecy surrounding the policy had made that task difficult.

''The committee was frustrated by persistent claims that questions about OSB in general and the maritime incursions in particular were subject to the blanket public interest immunity claim which Minister (Scott) Morrison had previously made,'' it said.

with AAP

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