There are grave concerns for a 14-year-old girl missing in Queensland floodwaters as the regional city of Maryborough assesses the damage to its CBD.

Water has begun to recede in the city, about three hours’ drive north of Brisbane, after the river peaked at just under 10 metres on Sunday night.

A levee was protecting the CBD until an underground stormwater mechanism failed just before 2pm on Sunday, allowing floodwater to surge up through the drains and into the streets.

More than 30 inner-city blocks were issued with an evacuation order after the remnants of tropical cyclone Seth dumped 600mm of rain on the Wide Bay-Burnett region in two days.

As damage to homes and businesses is assessed, emergency services continue to search for a missing teenager swept away while fleeing a car caught in floodwaters with a 40-year-old man near Gympie on Saturday.

“It is an extremely difficult area surrounded by water, which has created hindrances to our search effort,” Wide Bay Burnett District Superintendent Michael Sawrey said on Monday.

Water police, divers, volunteers and aerial support are assisting with the search, and Prime Minister Scott Morrison said his thoughts are with the girl’s family.

“I have a daughter who’s 14 years old, so I can understand the terrible, terrible time that family must be going through at the moment,” he said on Monday.

Mr Morrison also gave his condolences to the family of a 22-year-old man whose body was found in a submerged ute at Kanigan, north of Gympie, on Saturday.

Meanwhile, a father and his young daughter have survived two nights spent clinging to a tree before they were rescued over the weekend.

An RACQ rescue helicopter crew from Toowoomba airlifted the pair from a homestead in the Gympie region to hospital on Sunday after they were found at around 1pm.

“The father explained to the crew that his car had been caught between two sections of floodwaters on Friday night and water began filling the car,” RACQ LifeFlight said in a statement late on Sunday night.

“He and his primary school-aged daughter climbed onto the roof of the vehicle but were swept into the water in the darkness.”

They were washed into a tree, which they clung to.

On the first night, the father swam back to the submerged car and grabbed a rope, which he used to tie himself and his daughter to the tree.

After the water subsided on Sunday morning, the pair climbed down more than 10 metres to the ground and made their way to the homestead to raise the alarm.

“They had suffered exposure, dehydration and a lot of insect bites,” RACQ LifeFlight said.

It was one of at least two flood-related missions in the Gympie region for chopper crews on the weekend.

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