Officials at the Saint John Regional Correctional Centre were cleaning up and assessing damages Sunday, following a Saturday riot.
Sixteen of the 153 inmates barricaded themselves in one of the units, resulting in a lockdown of the entire facility.
No one was injured, but the prisoners caused "extensive damage," said Meghan Cumby, spokeswoman for the Department of Public Safety.
"The Saint John Police department is conducting a criminal investigation into the incident and will determine what charges may be laid as a result of this disturbance," she said.
Police have declined to comment and it remains unclear what sparked the incident.
Cumby said she did not know the nature of the damage — whether property was broken, flooded or burned.
But District Fire Chief Joe Armstrong confirmed there was a fire in one of the cellblocks.
"They kept it to the room of origin and they knocked the fire down fast, our crews did," he said.
"They were there most of the day. It started at 9:48 in the morning and this was at 12:23 so they were probably on-scene for about four or five hours."
Fire and police officials were on standby at the jail on Old Black River Road much of the day, but the matter was resolved by staff, Cumby said.
"The staff at the correctional centre are to be commended for their professionalism in dealing with the inmates and regaining control of the unit," she said.
The inmates who were involved were transferred to other units or other facilities within the province.