The Hunter Region SES has been handing out sandbags as the region prepares for torrential rain and thunderstorms.
The Weather Bureau has forecast intense rainfall across the day, with between 100 and 200 millimetres expected in parts of the Hunter.
Already, 117 millimetres has been recorded at Dungog in just one hour this morning.
A Severe Weather Warning has been issued for the Hunter, with the warning area extending to the Upper Hunter and Mid North Coast.
Newcastle, Lake Macquarie and Port Stephens are on flood watch along with the Lower Hunter, Paterson, Karuah and Williams Rivers and the Wollombi Brook.
