The disturbances began on Sunday after a detainee who had escaped the camp was found dead outside.
Inmates lit fires inside and barricaded themselves in a compound with weapons.
Immigration authorities said five detainees had non life-threatening injuries or medical conditions, but it was not clear whether they were sustained over the last three days of unrest or after police moved in.
`Group of criminals`
Police reinforcements arrived at the detention centre early on Tuesday to restore order. Reports said a hard core of detainees were confronting guards and refusing to return to their cells.
"Some force was used with a core group of detainees who had built barricades and actively resisted attempts to secure compounds, including threatened use of weapons and improvised weapons," authorities confirmed in a statement.
Some common areas appear to be severely damaged, it added.
Immigration Minister Peter Dutton blamed the disturbances on "a core group of criminals".
"We have been very clear about the fact that the government`s not going to cower in the face of the activities of some of these criminals," he said.
Inmate`s death `sparked riot`
Christmas Island is a remote outpost located 2,650km (1,650 miles) northwest of Perth and 380km south of Java in Indonesia.
It is part of Australia`s network of offshore processing centres for irregular migrants who arrive by boat, and also houses New Zealanders facing deportation from Australia.
The unrest started when a group of Iranian inmates staged a protest about the death of an Iranian Kurd, Fazel Chegeni.
Mr Chegeni had broken out of the facility on Saturday. His body was found at the bottom of a cliff on Sunday.
Mr Dutton told parliament he had been advised there were no suspicious circumstances.
Chart showing the number of people in Australian immigration centres and the amount of time they have been detained
It is difficult to verify information about what happens on Christmas Island as the media are generally barred from reporting there.
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