NZ volunteers arrive in Queensland

New Zealand help has touched down in Brisbane to help Queensland's flood recovery and clean-up.

State Emergency Services Minister Neil Roberts said 15 response team volunteers from across the Tasman on Saturday would head to Condamine after 42 of the town's 60 homes were inundated.

"There's a very long road to recovery ahead and the support we continue to receive from international and interstate sources is very much appreciated," Mr Roberts said in a statement.

The town's entire population of 150 was ordered to evacuate on December 30 as the Condamine River rose to a record 14.25 metres.

Black Hawk helicopters were called in for a rapid response, ferrying residents to nearby Miles and Dalby.

The volunteers are due to return to New Zealand on Wednesday.

Meanwhile, huge downpours in Queensland's southeast are rapidly heading towards Maryborough and could leave 20 homes and businesses inundated.

Up to 300mm fell in the Mary Valley in the 24 hours to 9am on Saturday and the deluge is expected to produce a major peak in the Mary River at Maryborough on Sunday morning.

The weather bureau said the river had reached 6.7 metres at 3pm on Saturday and was expected to reach at least nine metres on Sunday - the highest level since 1968.

Fraser Coast mayor Mick Kruger says he is closely monitoring the river levels.

"Tomorrow we might be in big trouble," Mr Kruger told AAP.

"A lot of the backwater will come up through part of the CBD, residential areas at the lower end of Ann Street will be inundated, and other pockets of areas that will experience similar situations."

On Saturday, emergency services were doorknocking residents in the low-lying areas of The Pocket, Kent Street in the CBD and Portside, warning them they may have to evacuate.

"Up to 20 homes and businesses could be inundated," Mr Kruger said.

"At this stage, none are affected."

Nationals' leader and the federal member for Wide Bay, Warren Truss, said the water levels were rising extremely quickly. On Saturday afternoon, the river rose 20cm in an hour.

"The forecast suggests this will be the worst flood in Maryborough for more than a decade, probably 20 years, could even be 40 years," Mr Truss told ABC Radio.

"Areas like The Pocket are going to get very wet."

The Granville Bridge is under water and isn't expected to be passable for a couple of days.

Mr Kruger said residents in Granville had been isolated already because of the floods.

"It's a self-contained suburb and we've got a temporary control centre set up at the hockey club with firies, ambulance and paramedics," Mr Kruger said.

The Lamington Bridge, south of Rockhampton, is also closed.

A bridge on the Bruce Highway, which bypasses the city, is unlikely to be inundated. Roads are cut off in Gympie, south of Maryborough.

Gympie received more than 102mm of rain in 24 hours to 9am (AEST) on Saturday.

The Mary River at Gympie was at a moderate flood peak of 14.3 metres.

The Bruce Highway, which has been closed at the Inglewood Bridge and Kybong, both south of the city, could be re-opened as early as Saturday night.

- AAP