The State Emergency Service in New South Wales has ordered about 2300 people in and around the town of Moree to evacuate their homes as the town braces for its worst flood since 1976.
The ABC reports Moree will effectively be cut in half on Thursday night when the council closes a major bridge and people are already on the move, packing up valuables and moving them to higher ground.
It is also recommending the evacuation of 2500 residents from the town of Wee Waa, 130 kilometres south of Moree, as rivers approach flood levels.
The SES also ordered evacuations in a township to the east called Pallamallawa and helicopters have been sent to collect anybody who needs to leave.
Wee Waa residents have been told to prepare to go within 16 hours.
Moree has been the focal point for the SES but a Bureau of Meteorology forecaster says the heavy rain is affecting 15 rivers in northern New South Wales.