Australian Federal Police officers have again used tear gas to contain a second night of protests at the Christmas Island detention centre.

An Immigration Department spokesman said five men protested on the roof of a building while security staff managed a small group of detainees protesting on the ground.

This morning police said all the detainees were now off the roof and the situation at the centre was "calm".

Ian Rintoul from the Refugee Action Coalition said he had been told at least 10 men had been on the roof, and small fires had been lit at the complex.

"At least 10 protesters on the roof have set fires to sheets. There have also been some smaller fires set in the yard of the detention centre," he said.

"Many of the people involved in the protest both last night and tonight are people who've only been there, you know, six or seven months, but like the others are facing the consequences of delays in their processing [and] a lack of transparency."

Federal Justice Minister Brendan O'Connor has played down the protest as a "small disturbance" and says the situation is now under control.

"As I understand it there was a small disturbance on Christmas Island and the Australian Federal Police had to respond to that," he said.

"There were a number of people that got on the roof and as I understand it, that disturbance has now been quelled and there is now calm again."

Immigration Minister Chris Bowen has warned the protesters that they face criminal charges.

He says they are achieving nothing and can expect to face the full force of the law.

"This is not a violent protest. This is simply criminal behaviour," he said.

"This sort of activity is completely inappropriate. It is way out of line with the expectations of the Australian people.

"People undertaking this sort of activity are achieving nothing except potentially their release from detention and transfer into a prison."

It is believed the unrest started around 9:00pm yesterday.

Police also fired tear gas and bean bag bullets on Wednesday during similar protests by about 50 detainees.