QUEENSLAND is facing a "potentially very deadly event", the premier says, but emergency services are ready for Cyclone Yasi.

Anna Bligh has headed into a meeting of the state disaster management group, where authorities will refine preparations for what could be the state's worst cyclone.

Forecasters say communities between Cooktown and Townsville are most at risk of a direct hit from Yasi, expected to cross the coast very late on Wednesday as a severe category four system with winds gusting above 250km/h.

Ms Bligh said everything possible was being done to prepare, including evacuations of low-lying areas at risk of tidal surges associated with the cyclone and discussions with the defence force about what help they might provide.

She said gale force winds could be felt along the north Queensland coast from as early as 8am (AEST) on Wednesday, and residents in the danger zone have a narrow window to prepare.

"This is a very, very big storm event," Ms Bligh told ABC radio before heading into the meeting, where the issue of compulsory evacuations would be considered.

She said the size of Yasi meant many communities either side of where it made landfall could expect to see the impacts of "serious storm surges, flooding torrential rain and gale force winds".

Ms Bligh said people must take the opportunity today to stock up on food and other supplies, with a real risk many could be without power for three to five days.

"I think many people will be very frightened by what they're hearing," she said.

"I don't want to frighten people, or panic them, but all the information I'm getting is that we are facing a potentially very deadly event.

"We have to make sure everybody knows what's in front of them so they can prepare themselves."

She said north Queensland residents would need to "prepare themselves mentally for what I think will be quite frightening to those who experience it".

"We stand ready. It's not a task that we expected. We thought we'd borne all that we would be expected to bear in the last five weeks.

"But it seems that more is to be asked of us."

She said extra police had been deployed into north Queensland and other backup teams were ready to go in once the cyclone had crossed the coast.

She said authorities would be doorknocking some low-lying areas today, urging at-risk residents to leave.

"I just appeal to everybody: if you have an emergency services worker or a police officer asking you to relocate please co-operate with them. They're trying to keep you and your family safe."