A powerful cyclone packing winds of up to 260 kilometres per hour roared across Australia's tropical northeast on Tuesday, uprooting trees, tearing down fences and knocking out power to thousands, officials said.

Cyclone Debbie, which slammed into the coast of Queensland state as a fierce Category 4 storm, quickly began to weaken after making landfall near the resort town of Airlie Beach, the Australian Bureau of Meteorology said.

By Tuesday night local time, it had been downgraded to a Category 2 storm, with winds gusting up to 155 km/hr.

One man was injured after a wall collapsed in Proserpine, a town south of Airlie Beach, Queensland Police Commissioner Ian Stewart said. The man was taken to a hospital, where he was in stable condition.

Strong winds and rain lash Airlie Beach on Tuesday. Wind gusts stronger than 260 km/hr were recorded at tourist resorts along the world famous Great Barrier Reef felt the effect of the powerful storm. (Dan Peled/EPA)

Early Wednesday, there were reports of significant structural damage to homes and public infrastructure from strong winds, heavy rain and huge waves. Two people were injured, including one person who sustained serious head wounds after being hit by a falling wall, police said. More than 51,000 homes were without power.

Queensland state premier Annastacia Palaszczuk said it appeared the worst-hit areas were the tourist magnet of the Whitsunday Islands off the coast and Airlie Beach and Proserpine, some 900 kilometres northwest of the Queensland capital, Brisbane.

'Battering ram effect'

The slow-moving storm pounded the coastal region for hours, creating what Stewart called a "battering ram effect," with the same areas enduring the howling winds and drenching rains for a punishingly long time.

Communities along more than 300 kilometres of coastline were expected to be impacted, Stewart said.

Australia's military was sending vehicles, aircraft and supplies to the region, with soldiers focusing on clearing debris and reopening roads, state recovery co-ordinator Brigadier Chris Field said.

John Collins, a member of the Whitsundays government council, was sheltering from the storm with his wife and four daughters inside their house in Proserpine.

It sounds like you got a jumbo jet sitting on the roof of your house - John Collins, local council member

He said he could see that four of his neighbours' sheds had been destroyed and every house within sight — including his own — had lost its fence. At least four trees had been smashed to pieces.

"It sounds like you got a jumbo jet sitting on the roof of your house," Collins said by telephone of the wind roaring outside. "It really is so loud. It's incredible."

A palm tree was knocked over behind a motel at Airlie Beach on Tuesday. (Dan Peled/EPA)

Collins's wife and two of their daughters were so scared they were hiding under blankets. Meanwhile, one of his other daughters — whom he described as "a real weather nerd" — was enthralled with the storm, and was diligently listening to the radio for updates on its path.