A small group of detainees has staged a protest on the roof of a block at the Christmas Island detention centre.

Tuesday's protest occurred as federal Opposition Leader Tony Abbott and his immigration spokesman Scott Morrison visited the island detention centre for a briefing, but it was unclear if they were anywhere near it at the time.

The latest action comes as a few detainees continue a rooftop protest at the Villawood detention centre in Sydney, where up to 100 rioters burnt down buildings last week.

Detainees are angry over lengthy delays in processing and the rejection of asylum claims.

A Department of Immigration spokeswoman told AAP that earlier on Tuesday eight detainees at the Northwest Point facility on Christmas Island had climbed onto a roof to stage a protest but by mid-afternoon only two were still on the roof.