The party's leader, Clive Palmer, has spoken out strongly in support of refugees, but told Fairfax Media the party would study the High Court judgment and any decision on allowing temporary protection visas would be made by his party room.

Mr Morrison re-imposed the refugee intake cap in March after the Senate voted down his attempt to re-introduce temporary protection visas (TPVs) for boat arrivals, declaring that the Coalition would "not give an inch when it comes to protecting our borders".

He vowed then to take "every step necessary to ensure that people who arrive illegally by boat are not rewarded with permanent visas". Mr Morrison, who has presided as minister over six months without a boat arrival, was travelling when the judgment was handed down and was unavailable for comment.

His March decision effectively imposed a freeze on the grant of permanent protection visas to about 1400 asylum seekers who had already been found to be refugees and has implications for many thousands more whose claims have not yet been decided.

"This is a very significant victory for the rule of law being brought to bear on the plight of refugees in our country," said lawyer David Manne, who led the legal team representing an Ethiopian teenager who arrived in Australia without a visa last year, after stowing away on a cargo ship.