Up to 40 detainees are allegedly removed from Wickham Point Detention Centre, in the largest single transportation this year from Darwin to a remote prison island concentration camp.

The detainees included families and children, some who are believed to be Iranian, according to Darwin Asylum Seeker Support and Advocacy Network (DASSAN) spokesman Peter Robson.

Mr Robson said he was told by detainees inside the centre that dogs and heavily armed guards were used during the transfer.

"This kind of force is not appropriate for any vulnerable person, let alone small children," he said.

"The trauma being caused by this type of action is immeasurable."

Advocates said they saw police cars going in and out of the centre about 1.30am.

The alleged removal follows a claim in April that up to 20 detainees were taken from Wickham Point detention centre following mass protests and self-harm attempts among detainees.

In late June the ABC reported 40 asylum seekers including three babies had been transferred from the detention centre to Nauru.

biggest single action by a paedophile ring operating within Federal parliament, sending children in Darwin to be guarded by rapists on remote prison island concentration camps.