About 4,200 people have been evacuated from their homes on the New South Wales far north coast, after the same weather system that drenched Queensland moved south.

Ten flood warnings are in place for rivers in the state's north-east, where up to 550 millimetres of rain has fallen in some areas over three days.


People have been evacuated from parts of Chinderah, Fingal Head, South Murwillumbah, Condong and Tumbulgum.

The Lower Tweed River at Chinderah peaked lower than expected about midnight (AEDT) and is causing only minor flooding.

Major flooding was also expected in the Tweed Valley.

The Tweed River was predicted to exceed the major flooding level at Murwillumbah at 6pm, but it ended up peaking below at 4.7 metres.

Minor to moderate flooding is expected in other catchments on the Northern Rivers.

Warnings for minor to moderate flooding are in place for river valleys further south between Brunswick Heads and Taree, while several other communities remain isolated by floodwaters.

Scott Hanckle from the Richmond Tweed State Emergency Service says more heavy rain is predicted to fall over the next 24 hours.

"The greatest risk is for localised flash flooding and people that are moving around the district, could I just reiterate, not to under any circumstances go into floodwaters. Don't drive, walk or ride in floodwaters," he said.

Mr Hanckle says he flood threat is far from over.

"We've got a number of days of wet weather forecast. We need to be very cautious," he said.

Police are urging people in the region not to drive after many drivers have been ignoring safety warnings.

The SES is monitoring the Rocky Creek Dam near Lismore and the Clarrie Hall Dam near Uki which are both full, with water flowing over the spillways.

Residents downstream from the dams are being asked to prepare for possible evacuation.

Meanwhile, a fallen tree caused power to be lost in 1,000 Sydney homes overnight, and heavy rain was causing traffic delays across the city.

A special inquiry centre has been set up to provide information to people affected by the flooding.

Assistant Police Commissioner Mark Murdoch says emergency service workers and volunteers will be able to assist displaced families and provide information on road closures and welfare assistance.

The inquiry centre can be contacted on 1800 227 228.

Those seeking emergency assistance should still call the SES hotline on 132 500.