Sydney: Hospitals, hotels and homes in seaside cities in Australia's Queensland state were evacuated on Tuesday as a monster cyclone intensified to 'deadly' proportions and roared towards the populous coast.

Severe Tropical Cyclone Yasi, packing winds of around 250 kilometres (160 miles) per hour, was on course to slam into the holiday resort-strewn coast early on Thursday, bringing with it treacherous storm surges and heavy rains.

"This storm is huge and it is life-threatening," Queensland Premier Anna Bligh warned as one of the worst cyclones in the region's history sent residents and tourists fleeing.

"This is potentially a deadly storm and we need to take it absolutely seriously."

Authorities ordered the evacuation of two hospitals in the port city of Cairns, where 122,000 residents are in the direct path of the massive storm that is threatening a 650 kilometre-long front.

More than 250 patients were to be flown out of Cairns by military aircraft as emergency officials warned a 2.5-metre (yard) storm surge could swamp the centre of the city popular with tourists and divers from around the world.

Mandatory evacuations were ordered in the most vulnerable coastal areas, while other residents also chose to head to evacuation centres. A total of 9,000 people were expected to be evacuated from around Cairns.

"If you are in a low-lying or waterfront area in the danger zone and beyond you need to relocate yourself and your family to safety," Bligh urged.

The state is still reeling from a record deluge and floods that have destroyed tens of thousands of homes and killed more than 30 people since December.

"I know that many of us will feel that Queensland has borne about as much as we can bear when it comes to disasters and storms, but more is being asked of us and I am confident that we are able rise to the challenge," Bligh said.

Yasi is expected to reach a severe category four on a five-point scale by the time it makes landfall, likely eclipsing Cyclone Larry -- a 2006 storm that caused up to Aus$1.5 billion ($1.5 billion) in damage -- in both intensity and size.

The storm is set to hit between Cairns and the town of Innisfail to the south at around 1am Thursday (1500 GMT Wednesday), but meteorologists predict its winds and rains could be felt hundreds of kilometres away.

"It's continuing to intensify," said meteorologist Ann Farrell, adding that Yasi was Tuesday afternoon about 1,100 kilometres east of Cairns and moving towards it at about 35 kilometres per hour.

But flood-weary residents in Queensland's south were expected to win a reprieve as Yasi was heading further north than first predicted and was not expected to trigger further flooding in already-devastated areas.

Airlines on Tuesday staged additional flights to far north Queensland to evacuate thousands of residents and tourists from the region before wild winds force the closure of airports as early as Wednesday morning.

Holidaymakers in the tourist paradise of Hamilton Island in the Whitsundays chain were abandoning the white beaches and evacuating their plush suites before flying to safety.

"We have asked our guests and residents to postpone the remainder of their holidays and we are helping them to arrange their flights out," Jill Collins of the Hamilton Island resort told AFP.

"The main thing is the safety of our guests, staff and residents. We hope for the best but have to prepare for the worst at times like this."

Dogs and cats were also being airlifted on Tuesday out of the city of Townsville, south of Cairns, as animal protection services sought to move them out of Yasi's destructive path.

Officials warned locals who were battening down the hatches to secure "anything that could become a missile in the winds" before leaving their homes and to stock up on food, fuel, batteries and candles.