Refugee advocates say about 80 detainees will be able to keep their phones as a result of the temporary injunction imposed by the court on Sunday. The injunction was ordered just hours before the seizure was due to commence.

Lawyers from the National Justice Project launched the proceedings on Sunday, leading to a five-hour special weekend hearing.

Without the injunction, detainees' phones at centres in Sydney, Melbourne, Yongah Hill in WA and Christmas Island would have been taken.

"We are thrilled," said refugee advocate Pamela Curr.

"It's just an interim injunction until the matter is thrashed out, but these mobile phones are a lifeline for people in detention. They need to be able to contact lawyers, or talk to family and friends in the middle of the night when they are feeling miserable."

Access to landlines is heavily regulated by detention centre operators and does not provide adequate privacy, she said. She believes the Border Force is trying to make it harder for detainees to have contact with the outside world.

Detainees are not allowed to have phones with cameras or recording apps. Under current rules authorities can take phones under certain circumstances, but the injunction means they cannot implement a blanket ban.

The court will conduct a full hearing at a later date.