A historic military response to the east coast bushfire crisis has been mobilised by the Morrison government, which has issued a compulsory call-up to 3000 Australian Defence Force reservists who will work with communities in NSW, Victoria, South Australia and Tasmania.

Mr Morrison said the “posture” of the federal government had shifted from reactive to proactive - moving from responding to assistance requests from states to actively leading elements of the bushfire response.

“There is still a very long way to go and there are clearly communities that need additional help,” he said.

Mr Morrison said federal governments had "traditionally always acted on the posture of the respond to request" from the states, but the devastating fire season across the country, which has months to run over summer, had spurred a direct intervention from the Commonwealth.