Three British tourists have been rescued from the roof of their campervan, after waking up to find themselves surrounded by floodwaters in a crocodile warning area in far north Queensland.

Swift water rescue teams were called to a camping at Green Patch, just south of Cairns, at about 6:00am today.

The picnic area was dry when the group parked there in their Scooby-Doo styled campervan last night, but the water rose around them during a huge overnight deluge.

Queensland Fire and Rescue officer Guy Bulmer was the first on the scene.

"The water levels were up the [at the] window level of the vehicle and there were three English backpackers on the roof," Mr Bulmer said.

"There was a croc sign almost right next to the vehicle."

"It was good they decided not to try and self-evacuate from the vehicle with water levels rising rapidly — and it had some flow.

"You just don't know what's in those flooded waters; there could be crocodiles or other obstacles that could cause injury".

There has been falls of up to 350 millimetres across the far north over the past 24 hours.

Weather forecaster Sean Luscombe said there had been a flood watch in place for the coast between Cooktown and Ingham.

"We will see a continuation of this rainfall throughout the day as that south-easterly surge moves up the coast, so heavy falls between Cooktown and Innisfail, " Mr Luscombe said.

Senior Constable Heidi Marek from Cairns Police warned motorists to drive to the conditions after two accidents on the Kuranda Range Road, north of Cairns.

"We've also had a tree come down on the Gillies Highway so we're asking drivers to check road conditions before they set off on their trip," Senior Constable Marek said.