Australian police used tear gas to put down a two-day riot at a migrant detention centre yesterday, where detainees, reportedly armed with machetes, chainsaws and petrol bombs, were running amok.

Reinforcements were sent to the remote Christmas Island facility after violence erupted and fires were set in a protest triggered late Sunday by the unexplained death of a man.

"The department can confirm all areas of the Christmas Island Immigration Detention Facility are under the full and effective control of service providers and department staff," the Immigration Department said in a statement.