The Australian-based Refugee Action Coalition says Canberra cut off all phone and internet communication from its detention camp on Papua New Guinea's Manus island for three days in what it says was an act of reprisal.
The Coalition says Australia's Department of Immigration cut links because asylum seekers had sent photos of the conditions on Manus.
It says phone calls are now being monitored.
However, the Coalition says the detainees have the right to communicate with their relatives, or anyone else, without the Australian government listening in.
It says detainees are still confined to the Manus camp even though they had been told they would be allowed to move freely around the island.
Australia has been criticised by international organisations for the way it is treating its asylum seekers in the camps it set up abroad last year.
The opposition in PNG is seeking a Supreme Court determination over whether the Australian detention camp is compatible with PNG's constitution.