NSW towns 'on edge' amid 30 flood warnings

A storm system moving across the Gold Coast and much of northern NSW dropped up to 220 millimetres of rain on Thursday night, leading to flood warnings for 30 river catchments across NSW and southern Queensland.

The SES doorknocked homes in the Tweed Valley village of Chillingham overnight to warn of expected moderate flooding while people in low-lying areas of Lismore were warned they could be cut off by rising water on Friday evening.

"This is probably us for a couple of months yet and that's going to be a very challenging thing for us to deal with," Resilient Lismore coordinator and local councillor Elly Bird told ABC Radio on Friday.

Storm systems will travel further south to the Blue Mountains on Saturday bringing the risk of flash floods, strong gusts and downed trees and powerlines.

The Darling, Macquarie, Lachlan and Murrumbidgee rivers are key focal points for the SES, in addition to the Northern Rivers region.

Gunnedah, home to 9000 people, was expecting the Namoi River to reach major flood levels on Friday evening, ahead of a peak early on Saturday.

Downstream, the well-prepared NSW cotton town of Wee Waa and its eight-kilometre levee will likely remain surrounded by floodwater until Wednesday, the local council says.

"(But) it's ruined all of our local roads again - we're still looking at funding for damage from flooding in 2020," Narrabri Shire Mayor Ron Campbell told AAP.

"If we get substantial rain across the summer, we could have a record flood for sure - probably something not seen since the 1970s."

Meanwhile, Gold Coast Council opened three sandbagging stations on Friday, as Hinze Dam reached 102 per cent capacity and beaches were closed.

A special school, a dental business and a storage business were among those inundated in the Gold Coast hinterland.

About 260mm of rain fell in 24 hours at organic farmer David Freeman's Currumbin Valley property, wrecking his leafy greens and potentially spelling the end for half of his 300 avocado trees.

"They're very sick as a result of the last 12 months of heavy rain because of the saturated soil ... and this deluge is just going to re-saturate the soil and will cause more soil fungus problems," Mr Freeman told AAP.

"(The rain) is weighing heavily on farmers because we just got trashed in the early part of this year."

The wet weather had caused huge anxiety for the Tumbulgum community on the Tweed River, Husk Distillers co-owner Harriet Messenger told AAP.

"Everybody in the region is always very on edge - particularly so close to another major event," she said.

The business makes rum from sugar cane grown on its farm, using cows to eat and process sugar cane waste on site.

In the small northern NSW town of Glenreagh, punters are flooded in at its only pub, the Golden Dog Hotel, after the Orara River reached minor flood levels on Friday.

NSW Emergency Services Minister Steph Cooke warned against complacency.

"I know there are many communities across NSW that are flood weary," she said.

There were fourteen flood rescues on Thursday and Friday, one of which saw a police officer wade into a swollen river west of Dungog to save three people including a four-year-old boy lifted through the rear window of a car.

Australian Associated Press