Yesterday, Tropical Cyclone Charlotte, which was recategorised as a tropical low by mid-morning, brought more than 400mm of rain to some parts around Cairns.

Cape Tribulation received 436mm to 9am yesterday, almost as much as Melbourne received all of last year (449mm)

The Bureau of Meteorology predicted heavy rain and localised flash flooding to continue overnight and into today.

A flood warning was issued for coastal rivers and streams between Cairns and Townsville, with another high tide due late this morning.

State Emergency Services (SES) received 300 calls for assistance yesterday as the heavy rain combined with a king tide to create floods across the region.

Mel McAlonan, deputy controller of the SES's Innisfail unit, said the day was spent frantically sandbagging residences, as well as the dialysis unit of the local hospital and the fire station.

"We're just flat out at the moment. We've still got 30 to 40 jobs to go and there's more heavy rain on the way so it could be just as bad tonight," Ms McAlonan said.

"It will be all hands on deck for 24 hours, I'd say."

Mayor Val Schier returned to Cairns at 5.30am yesterday following an overnight flight from Perth and "got home to a very wet city".

"Cairns is low-lying in a lot of areas but no matter of planning or infrastructure can with that sort of rain," Cr Shier said.

"A couple of the old-timers were saying it hadn't flooded quicker than that in many, many years."

Sewers were backed up around the city and debris carried by floodwaters had blocked drains, she said.

"The phones were going crazy with drains blocked and sewage backing up but we're just waiting for the water to go down before we can fix it."

Wayne Hepple, area director for Emergency Management Queensland, called on residents in four-wheel drives to be considerate when driving around the flood-hit streets.

"People need to be considerate. High-clearance vehicles that go driving around can push waves back into yards and houses that did have a couple of inches clearances, Mr Hepple said.

"Those people were dry and now they're wet."