The weather system, which made landfall on Saturday, has battered a 400-kilometre (250-mile) stretch of coast for five days, claiming one life when a driver was swept off a bridge Friday.

Even as the wind and rain eased, authorities issued a string of flood and severe weather warnings across the region, which straddles Queensland and New South Wales.

"This event is far from over," Prime Minister Anthony Albanese told a news conference in the flood-hit New South Wales city of Lismore.

"We need to continue to not be complacent."

The tropical depression dumped 30 centimetres (one foot) of rain in 24 hours over parts of Queensland's capital city of Brisbane, the bureau of meteorology said.

Floodwaters swamped some streets in the city and its surrounds, stranding half-submerged cars in the worst-affected areas, images published in Australian media showed.

Emergency services rescued 17 people from fast-moving waters in Queensland overnight, the state's premier, David Crisafulli said.

"Rainfall is leading to flash flooding as well as river flooding in parts of the southeast," he told a news conference.

"We are urging people to stay connected because of the prospect of more intense flooding during the course of today."

- Flash flooding -

Heavy rainfall, flash flooding and moderate-to-major river flooding remained a risk, bureau of meteorology forecaster Jonathan How said.

"This is all due to the remnants of ex-Tropical Cyclone Alfred," he told AFP.

"It did cross the southeast Queensland coast on Saturday, but it has been very slow moving even as it moved over land. And, quite importantly, it is still dragging a lot of moisture."

Utility companies said more than 185,000 homes and businesses were still blacked out in Queensland, and another 10,000 in New South Wales.

In New South Wales, "helicopters are being used where possible to survey remote areas of the network to help identify the damage", a spokesperson for Essential Energy said.

- 'Unpredictable' -

"The weather pattern is still somewhat unpredictable. We're expecting some increased rainfalls over the next 24 hours," New South Wales Premier Chris Minns told a news conference.

Nevertheless, all but one of the evacuation notices in the state have been lifted, he said.

The wild weather has so far claimed at least one life, after a 61-year-old man's four-wheel-drive pickup was swept off a bridge Friday in northern New South Wales.

He tried in vain to cling to a tree branch in the river before disappearing into the rapid waters, police said, and his body was found the next day.

In a separate incident Saturday, 13 soldiers were injured and taken to hospital when two army trucks rolled over during a deployment to clear roads near the flood-prone northern New South Wales city of Lismore.

All but one of the troops had been released from hospital by Monday, Defence Minister Richard Marles said.

"The one person who is still in hospital is in a stable condition. Not a life-threatening injury, and is expected to recover," he told national broadcaster ABC.