Communities on the Queensland-NSW border are on high alert for flash flooding after more than 20 centimetres of rain fell in just three hours in some areas.

An intense weather system moved east overnight across the Gold Coast and the already-soaked NSW northern rivers, prompting emergency text messages to be sent to residents in four local government areas.

Several areas received 100 millimetres of rain in a few hours. The highest totals were 30 kilometres inland of Coolangatta, at Couchy Creek and Upper Springbrook, which each copped 222 millimetres in three hours.

“This type of intense rainfall on top of our wet catchments does lead to flash flooding and results in some rivers rising very quickly,” NSW SES superintendent Tony Day said on Friday.

“It’s a dynamic situation that puts vulnerable communities at risk.”

All residents and visitors should consider their travel plans, check on neighbours and review their emergency plans.

“Just because it was safe last time doesn’t mean it will be safe again,” Mr Day said.

A number of inland river catchments are flooded and are expected to stay that way for several months.

Multiple climate drivers were behind the scenario, including a rare third consecutive La Nina year.

“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.

Meanwhile, the Gold Coast was under a severe thunderstorm warning on Friday morning with heavy rainfall and damaging wind gusts possible about the coastal fringe, the Bureau of Meteorology said.

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River and creek levels in the Nerang and Coomera Rivers catchment were rising rapidly overnight.

Elsewhere, major flooding was occurring at cotton towns Wee Waa and Warren in the NSW north-west.

The Peel River, which flows through regional centre Tamworth, peaked at 4.94m about midnight. By early Friday, it had fallen below the moderate flood mark.

The SES said it had conducted four flood rescues, including one on Thursday morning in which a police officer used a rope and a winch to save a four-year-old boy and two women from a swollen river west of Dungog in NSW.

– AAP