SYDNEY, March 28 (Xinhua) -- Residents in the Australian state of Queensland are buckling down for Cyclone Debbie, a category four storm system bearing down on the north of the state.

The eye of the storm is measured at over 100 km wide and is expected to hit the mainland between the cities of Mackay and Townsville at around 14:00 AEDT.

Authorities have warned that gusts could reach in excess of 275 km per hour with sustained winds of 175 km per hour.

Queensland Premier Annastacia Palaszczuk told local media that "this is going to be a monster of a cyclone," and that authorities are "very concerned."

More than 25,000 people have been evacuated in the last 24 hours, which is the largest evacuation operation ever seen in the state.

Problems for low-lying areas have also been compounded by flood warnings, as an extremely high 2.5=meter tide encroaches Queensland riverlands and the city of Mackay.

The emergency services have sent 2,000 extra staff from a number of different agencies to the storm zone and 600 more hospital beds have been made available for the injured.

Energy Australia have also made 800 staff available to restore power as soon as possible.

Already, Cyclone Debbie is making its way through the Whitsunday Islands with winds of 190 km per hour being recorded by the Bureau of Meteorology.

It has been reported that roofs have been torn from buildings on the islands, with a tourist telling the Australian Associated Press "I have never heard gusts of wind howl this loud and this intense before."