North Queensland battles against floods

Children and tourists have been rescued and pregnant women airlifted to hospital as north Queensland struggles under floodwaters.

The weather bureau expects flood levels in the Herbert River to remain into Thursday, causing further problems for the worst-hit town of Ingham, where 2,900 homes have been affected by heavy rain brought by ex-tropical cyclone Ellie.

Hundreds of people have evacuated from inundated homes to a temporary shelter at the high school or the higher and drier homes of friends and family.

The bureau is also keeping an eye on a monsoon trough off Cairns which forecasters say has a "moderate" chance of becoming a cyclone on Friday.

Hinchinbrook Shire Mayor Pino Giandominico said the situation was "heartbreaking".

"It's affecting people's life, people's jobs and their businesses," he said.

"People think once the water recedes it's all over, but once it recedes that is when the work is going to start."

The clean-up is expected to start in earnest once the Herbert River - which peaked at 12.25 metres - falls to below seven metres.

Late on Tuesday night, two pregnant women were transferred to Townsville hospital by helicopter as a precaution.

Four children playing in floodwaters were rescued.

At Conjuboy, west of Ingham, four tourists - one aged 75 - who were marooned on top of their car in the flooded Eight Mile Creek were rescued by police.

Other than mild hypothermia, the tourists were uninjured.

More than 100 weary SES workers will be relieved by two teams from Brisbane, as well as Red Cross and Army personnel in coming days.

Queensland SES director Mark Dole said the initial relief teams were trained in flood boat operations but extra help would be provided for the clean-up once water levels dropped.

Mr Dole said the emergency workers were well aware of the dangers of working in the tropics.

"The team that's just left Brisbane was asked what they're expecting and they said 'A lot of floodwaters and maybe the occasional saltie' (crocodile)," he said.

Deputy Premier Paul Lucas, who visited Ingham on Wednesday, said he didn't believe the ground could cope with more rain.

"It's like pouring water over a wet towel," Mr Lucas said.

Ingham received 366mm of rain in the 24 hours to 9am on Wednesday, on top of more than 400mm dumped in the previous few days.

Ingham father of two David Harkin was preparing on Wednesday to evacuate after watching water run through his two-level home since Monday.

He's seen several snakes around his Fairford Road home in recent days.

"That's why I keep the broom here (at the front door) to chase the snakes away," he said.

On Wednesday, the state government opened a centre to provide cash assistance for food, clothing, medication and emergency accommodation.

Means-tested assistance will also be available for uninsured essential household contents and repairs to structural home damage.

Meanwhile, residents of Normanton in the Gulf of Carpentaria and nearby cattle stations evacuated themselves as the Norman River peaked at 6.3 metres.

Fresh food supplies were flown in to Normanton and Karumba on Wednesday.