The 120 personnel already on the island are also helping fire crews prepare for another dangerous fire day on Thursday, bringing in heavy machinery to bolster containment lines.

A big focus so far has been restoring water supplies with a portable treatment plant flown in to do the work of infrastructure damaged in Friday's blaze.

Islanders have been asked to restrict water use to essential needs after the plant near Parndana was knocked out of action.

Work is also underway to help farmers deal with dead livestock, clear roads and recover injured wildlife.

"I'm building up what will be a 600-person group here on the island over the next two days," Brigadier Damien Cantwell said.

"They will be made up of both high readiness units across the defence force but also a contingent of reservists behind them so we can sustain the ADF effort."

Brig Cantwell said as local commander he had the full support of the ADF leadership to deploy any resources required to aid in the recovery efforts.

Defence force personnel have set a totally self-sufficient staging ground just outside Kingscote, the island's main town.

Those deployed are being urged to also use their downtime to support local businesses which might be doing it tough, including cafes and restaurants.

They arrived on the island on Monday after travelling in convoy from Adelaide.

Australian Associated Press