Video Extras

Northern New South Wales Told To Brace For 'Concerning' Weather In Coming Days

Northern NSW is bracing for more wild weather as emergency officials warn of a "concerning weather system" off the coast that is tracking towards land.

The widespread rain is predicted to last for another week and the Bureau of Meteorology also says there is an increased chance of unusually high rainfall - in the top 20 per cent of historical records - for March to May in much of eastern NSW.

The forecast comes after parts of the far north coast reported more than 240mm of rainfall in the past 24 hours, with six people being rescued from flood waters.

The northern rivers town of Mullumbimby recorded 45mm in just 30 minutes on Thursday morning, while Whiporie recorded 90.8mm in three hours and the town of Alstonville copped 240mm in the past 24 hours.

Emergency crews took more than 1100 calls for help in the Sydney area in the past 48 hours.

"Our focus is now very much shifting to that north coast and the far north coast of NSW with that very concerning weather system ... sitting just off the coast and due to make land fall," SES Assistant Commissioner Dean Storey told the ABC on Thursday.

The area was already a "key focus" after a number of flood rescues were carried out in the past two days, including six in the past 24 hours, he said.

Communities are being urged to be aware of risks in their local areas and monitor changing forecasts.

"If you live in a flood prone area, know what you would do and your family would do if you needed to evacuate your home, Mr Storey said.

"It's been a very wet summer. The soil is saturated, rivers are full, dams are full.

"Any additional rainfall will have a very concerning effect than it would in a normal area."

A severe weather warning is in place for Tenterfield, Dorrigo and Bellingen on Thursday, which will likely continue to Friday.

The BOM says six hourly rainfall totals of up to 70 to 100mm are likely, increasing to 100 to 160mm over areas east of Kyogle and Grafton.

An initial flood watch was issued for parts of the northern rivers and mid-north coast on Wednesday afternoon, affecting the the Tweed, Brunswick, Wilsons, Richmond, Orara, Bellinger and Nambucca Rivers.

The BOM advised rain in the catchments could cause minor flooding on Thursday and Friday.

The rain is being caused by a strong upper trough and low pressure system, which is moving slowly in a southern direction across Queensland on Thursday.

A surface trough on the northeast coast is deepening as it responds to the upper system.

The surface trough will move slowly on Thursday and Friday, and will produce heavy, persistent rainfall and thunderstorms over those days.