Tropical Cyclone Koji has developed off the North Queensland coast and is set to hit the hard-hit state as a category two system in less than 24 hours.

Tropical Low 12U, northeast of Ayr, developed into a tropical cyclone system on Saturday afternoon and is slowly moving towards the coastline.

The Bureau of Meteorology’s track map shows Koji moving towards Ayr by 4am AEST on Sunday as a category two system.

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“The coastal crossing is forecast for early Sunday morning between Townsville and Bowen. After crossing, Koji will weaken and then track generally westwards,” the bureau said.

A category two system will have sustained winds of 95km/h near the centre and gusts of 1130km/h, causing moderate damage with roof and structural impacts to homes and significant power outages.

The bureau’s track map shows the cyclone will impact between Innisfail and Mackay.

Koji is currently in the coral Sea and is moving at 13km/h.

Winds of up to 130km/h are possible from Saturday evening into Sunday morning for exposed coastal locations from Townsville to Proserpine.

Damaging gusts of up to 100km/h are expected between Cardwell and Airlie Beach on Saturday evening and could extend further north to Cardwell if the cyclone tracks further west.

The bureau added these conditions could also extend towards Mackay and adjacent inland areas overnight and into Sunday morning.

“Gales are expected to ease as the system crosses the coast and moves inland during Sunday,” the bureau said.

As for heavy rainfall and flooding, Ingham and Proserpine are in the firing line on Saturday night.

Townsville to Mackay may also experience dangerous and life-threatening flash flooding on Sunday.

The bureau’s Angus Hines earlier warned of six-hour rainfall totals of between 90 and 170mm from Cooktown to Mackay, and 24-hour rainfall totals up to 350mm.

From Sunday, he said the focus would shift southwards, with the tropical low gradually moving inland from central Queensland impacting the central coast, Capricornia, central highlands and possibly down to the southeast.

The tropical low is set to bring heavy rain to the already-drenched north. Credit: AAP

Hines predicted that multi-day totals up to 500mm from Cairns to Mackay were possible, with between 150 and 300mm forecast from Mackay south to Gladstone.

The picture was less clear in the densely populated southeast of the state, but falls up to 100mm were possible, with most of the rain expected on Monday and Tuesday.

In the northwest, major flooding that has already heavily affected Gulf Country communities - where livestock losses are projected to be significant — continues on the Flinders River.

Major flood warnings have also been issued for the Herbert, Haughton and Tully rivers.

But Hines warned that a far greater area could be affected.

“Given how much rain is still to come, we absolutely could see other rivers anywhere along this northern coastline between Cairns and Rockhampton will see some flooding in the coming few days,” he said.

- With AAP.