Unrest broke out at an Australian island immigration detention centre, authorities and NGOs said Wednesday following reports the Christmas Island facility had been set alight by frustrated detainees.

The Australian Border Force said an operation was underway "to restore order after a disturbance" at the North West Point Immigration Detention Centre on the Australian territory in the Indian Ocean.

"A small number of detainees caused some damage to the facility overnight and continue to be non-compliant," the government agency said in a statement, adding there were no reports of any injuries.

Advocacy group Refugee Action Coalition said reports from inside the centre suggested two compounds had been set ablaze overnight Tuesday into Wednesday as tensions boiled over.

"While the extent of the damage is not known, the glare from the fires and the extent of the smoke in the air indicates the fires are substantial," the group said.

National Justice Project principal solicitor George Newhouse said detainees were increasingly frustrated with conditions after being confined to their rooms for up to 22 hours a day and unable to contact their families due to a poor mobile phone signal.

"The federal government have a policy of keeping detainees in harsh and inhumane conditions to force them to leave Australia," Newhouse said.

"These harsh and solitary conditions are having an effect on the mental health and welfare of detainees."

The Australian Border Force said the centre was being used to house "unlawful non-citizens" -- migrants who had their visas cancelled after being convicted of crimes -- but would not confirm how many people were currently being detained.

The Refugee Council of Australia said the facility held 220 detainees as at October 2020.

Christmas Island, a tropical isle off Australia's northwest, gained notoriety as a venue where asylum seekers who attempted to reach the country by boat were detained.

The government controversially reopened the facility last August after a two-year hiatus, saying mainland detention centres were filling up as the coronavirus pandemic prevented the deportation of migrants.

It was also used to quarantine Australians evacuated from Wuhan in February after Covid-19 was first detected in the central Chinese city.

hr/arb/axn