Government lawyers argue it would have been too dangerous for authorities to have told 157 asylum seekers they were being returned to India.

Australian authorities had to keep 157 asylum seekers in the dark about plans to return them to India because of fears of sabotage, government lawyers argue.

A case determining the federal government’s powers to remove asylum seekers from Australia’s contiguous zone, just outside territorial waters, and send them to other countries, will come before the High Court next week.

In submissions filed to the court, government lawyers argue it was too dangerous for border protection personnel to have consulted with the asylum seekers about their destination because they were outnumbered three to one.

There was a significant risk that, had they been informed they were being taken to India, they would have taken steps to prevent their efforts to reach Australia being thwarted, their submission says.

“(That would have included) by engaging in actions that may have jeopardised the safety of the Australian vessel,” the lawyers say.

The case centres on a male Sri Lankan asylum seeker who was among 157 people who set off from India on June 13.

Authorities intercepted the boat in Australia’s contiguous zone, 16 nautical miles off Christmas Island, on June 29.

The vessel became unseaworthy after a pump failure started a fire in the engine room.

The asylum seekers spent almost a month in detention aboard the Customs vessel Ocean Protector. Cabinet’s national security committee had instructed Ocean Protector to take the asylum seekers to India and then later Australia’s Cocos (Keeling) Islands.

They have since been sent to Nauru for processing.

The lawyers dismissed claims the detention was unlawful. They insist it was legal for the ship to be travelling to India while negotiations were still underway with that country to receive them.

There was no right to procedural fairness under maritime power laws, the submission said.

It was impractical for border protection ships to be staffed with interpreters in order to give non-English speaking asylum seekers a say on where they wished to go.

“It would be impossible to anticipate far in advance the interpreters … who may be required,” the lawyers said.

The plan did not breach Australia’s non-refoulement obligations under international law, the lawyers argued.

The High Court hearing begins October 14.