The majority of the chambers are considered a total loss, with many important council documents and staff personal belongings irretrievable.

Staff will work from home, out of local libraries and at the Powerhouse Museum in coming days with no clear target for when the building will be up and running.

Damage is estimated to be worth $20 million and Liverpool Mayor Wendy Waller has said there will be a delay in processing development applications.

Anyone who may be able to assist the investigation is urged to contact Liverpool Police via Crime Stoppers on 1800 333 000.