Parts of northern New South Wales are starting to receive heavy rainfall as Queensland's storm system moves south.
The State Emergency Service says the largest falls so far have been in the Tweed area with 176 millimetres at Hopman's Creek.
More than 100 millimetres have been recorded further south in the Wilson, Brunswick and Richmond River catchments.
Long weekend travellers are being advised to take care on the roads and defer travel if possible.
A spokeswoman from the Richmond Tweed S-E-S, Janet Pettit, says the rain will get heavier.
"It's a slow moving low and it's currently tracking in a south south-west direction and it's bringing very heavy rainfalls, strong winds and high tides to the area with heavy surf.
"They're expecting between 70 to 110 kilometre wind gusts for some parts of the Northern rivers and they're also predicting totals in excess of 200 mils up in our area," she said.
A severe weather warning has been issued for the Northern Rivers, Northern Tablelands and Mid North Coast regions.
A flood watch is also in place for several coastal rivers.
Forecaster Dimitri Danchuk says tornadoes, like those in Queensland, are also a possibility.
"Currently, we are talking about damaging winds, but in the worst case some wind gusts could be distracted from.. tornados effectively should not be ruled out," he said.
Extra swift water rescue teams have been based in Coffs Harbour on the mid-north coast.
The local controller for the State Emergency Services, Bob White, says people have been getting ready.
"We have had people coming to us already, collecting sandbags.
"It's great that people are thinking ahead, and being a little bit pro-active, and not waiting until the last minute.
"We're providing sandbags and sand so they can take some care for themselves as well," he said.
Mr White says the floods that hit the mid-north coast in 2009 resulted in 90 flood rescues.
He says crews are prepared for a repeat of the same amount of water in the area.
"The possible rainfall that is predicted for the Coffs coast is rumoured to be quite extensive.
"It could cause flash flooding in the area. This could possibly be as bad as 2009.
"Rather than just leave it to a very small number of people who worked very very hard back in 2009, we're bringing extra resources into the area, so that we can be fully prepared and offer protection to the community," he said.
© ABC 2013
16:39 EST The mercury soared in the nation's southwest today with Perth recording its hottest September day on record, however heavy rain and cooler temperatures will arrive on Sunday.