The declaration gives the federal government power to intervene and deploy resources.
It is a legislative power that Morrison sought after the 2019-2020 bushfire crisis.
Morrison is also set to outline more money to help communities recover from floods on the east coast when he visits Lismore today, as government ministers expect anger from residents whose lives have been upturned.
The federal government has been criticised for the pace and scale of its response to the floods.
