A mother, along with her four children who have been trapped overnight on a rooftop, have been rescued by a helicopter, as flash floods continue to strike northern Queensland as an aftermath of Cyclone Oswald.

The Atherton family was caught outside right smack under the elements in their four-wheel drive when the rivers surrounding their vicinity rose beyond allowable levels, the Cairns Post reported. Without any means of communication, the father was forced to leave his family behind as he tried to cross the river to seek help. Walking a total of 25 kilometres, a helicopter was eventually sent to pick up the mother and the four children. All are alive and well.

As of 12:10 pm on Tuesday, residents in northern Queensland have been warned of potential flash floods and accompanying dangers, as a result of the heavy downpour that Cyclone Oswald, already downgraded from category one, had dumped into the Australian state.

The Bureau of Meteorology said Cyclone Oswald had left a monsoon trough in its wake. The heavy rainfall prediction is expected north of the monsoon trough, and could develop along the east coast southwards to about Townsville.

"The rainfall totals got up over 300mm throughout parts of the north tropical coast region around the Innisfail and Tully areas," Brett Harrison, BOM forecaster, told ABC radio.

"We can expect heavy rain to continue throughout the next few days with the monsoon trough."

Meanwhile, the Aboriginal community of Kowanyama had been cut off from the rest of Cape York Peninsula as floodwaters cut through its main access road.

Although no massive damage was reported, Robert Holness, Kowanyama mayor, said the absence of a major supply route is now their main concern.

Authorities are coordinating to ensure the delivery of food and medical supplies through chopper.

"That's our main priority now, getting air access," Mr Holness told AAP on Tuesday, adding supplies and people would most likely be flown from nearby Pormpuraaw.