There are flood warnings across NSW and Queensland as Cyclone Uesi stirs up hefty swells along Australia's east coast.

Heavy rain associated with the category-three system, which is about 1400 kilometres off Australian shore and tracking south of New Caledonia could mean rivers and creeks continue to rise.

With flooding still posing a major threat to communities, people in NSW have been advised to take steps to avoid property damage ahead of further predicted rainfall.

The Bureau of Meteorology said Cyclone Uesi won't make landfall in Australia, but its effects will be felt by coastal communities. 

The cyclone is expected to come close to Queensland on Thursday night or Friday, and then weaken as it moves south towards NSW, bringing rain, hazardous swells and high winds.

Parts of Queensland remain on flood watch, with warnings for coastal catchments between Bundaberg and the NSW border.

Click to see flood warnings for NSW and Queensland.

Southern inland regions are also expecting significant rain, including Dalby, which has flooded once in recent days and could flood again.

A severe thunderstorm is bearing down on Crows Nest and Haden, moving south and potentially causing flash flooding.

NSW bunkers down  ahead of further predicted rainfall

NSW and Queensland on flood watch as Cyclone Uesi nears Australia_1
Sydney had its heaviest rain in up to three decades last weekend. Photo: Twitter/NSW Ambulance

The SES said those with properties at risk of inundation should raise moveable items such as furniture as high as possible onto benches or tables, placing electrical items on top.

Farmers on low-lying land close to rivers and creeks were urged to monitor livestock, pumps and other equipment.

A very high chance of showers is forecast for Sydney, with 6-25 millimetres possible on Wednesday, and a further 15-35 millimetres on Thursday.

In the northern rivers, Byron Bay and Tweed Heads could each receive 15-50 millimetres on Wednesday. On the mid-north coast, Coffs Harbour could get 15-40 millimetres.

The BOM is saying 15-45 millimetres is possible in Nowra on Wednesday, with up to 80 millimetres on Thursday.

Also on the South Coast, Huskisson could get 20-60 millimetres of rain on Wednesday and 40-80 millimetres on Thursday. Ulladulla could receive 45-90 millimetres on Thursday.

The NSW coast was drenched at the weekend, with up to 550 millimetres of rain in parts of the northern rivers, mid-north coast, Central Coast, Sydney, Blue Mountains and the Illawarra.

Sydney had its heaviest rain in three decades and was battered by gale-force winds. Emergency services were still clearing fallen trees, removing debris and extracting cars from floodwaters on Tuesday.

On Tuesday night, the NSW SES said it had received 12,951 requests for help since last Wednesday night.

Tens of thousands of households in Sydney and the Central Coast were still without power on Tuesday night, with Ausgrid asking customers to prepare for outages into the weekend.

The NSW energy minister has confirmed Ausgrid's request to the military. 

Ausgrid said power had been restored to 109,000 customers after "one of the worst storms to hit our network in the past 20 years", but about 31,000 customers remained without power at 7am on Wednesday.

Fewer than 1000 Endeavour Energy customers also remain powerless.

"Customers are being advised to prepare for outages into the weekend … additional crews from Queensland, Victoria and South Australia are arriving to assist with the response," Ausgrid said.

-with AAP