A fresh High Court challenge could be launched after the Immigration Minister indicated he would personally apply a “national interest” test for permanent protection applications from people who arrive without a visa.

Two weeks after the High Court struck down the Government’s attempt to cap the number of protection visas for some refugees, Scott Morrison has moved to circumvent the decision.

• ‘Mothership’ refugee claims 
• Australia assessing refugees at sea

He has declared he will personally apply a “national interest” test for those who arrive without a visa and apply for permanent protection.

Refugee advocate David Manne has signalled a possible second legal challenge, telling the ABC the move is extraordinary.

This is clearly an act of desperation by Mr Morrison

“[It will] essentially defy the clear will of Parliament and the rule of law in this country,” he said.

Last month’s High Court decision was sparked by Mr Manne’s client, a 16-year-old unaccompanied boy whose case is still before the court.

Greens senator Sarah Hanson-Young says the Minister is thumbing his nose at the will of the Parliament and the ruling of the High Court.

“This is clearly an act of desperation by Mr Morrison,” she said.

“It is him [and] his department acting in a way that seems to be, not just above the law, but above the Parliament.”

It comes as the fate of dozens of asylum seekers reportedly being held at sea on an Australian Customs vessel remains unclear, after Mr Morrison refused to make public any details about the operation.

There have been reports in recent days that two asylum seeker boats have been intercepted by Australian authorities in the Indian Ocean and that the passengers of one of the boats are set to be transferred to the Sri Lankan navy at sea.

Mr Morrison refused to confirm the existence of the boat and would not address questions about whether the asylum seekers would be handed over to Sri Lankan authorities.