People bunkering down at home for the onslaught of Cyclone Yasi should prepare a safe room and not panic if their roof lifts off, Australian emergency authorities say.

Queensland State Disaster Coordinator Ian Stewart says people should be preparing the safest part of their homes, which is the bathroom or toilet in most modern homes.

He said people should gather mattresses, food, water and raincoats in that area and not move from there for any reason.

"They should be preparing themselves for the fact that the roofs of their houses may lift off, but that does not make the structure or the framework of the house any less sound," Mr Stewart told reporters.

"They get wet, but it is far more dangerous to panic and run out of the house than to stay bunkered down in that area and simply get a bit wet."

He said people also needed to be aware that emergency services personnel would not be able to respond in the 24 hours from about midday (AEST) on Wednesday as gale force winds hit and the cyclone passes through because they needed to stay safe as well.

"So people have to understand that they need to become first responders themselves to ensure the safety of their family, themselves and their neighbours," he said.

"But please, please do not take unnecessary risks. That would be a tragedy."

Residents have been warned the calm associated with the eye of the cyclone could last for up to an hour and to not go outside during that time.

All electricity, gas and water supply should be turned off and all appliances unplugged.

Windows must be taped in a crisscross fashion with strong packing tape to prevent shattering.

Residents should have cash at hand, as power outages could see ATMs out of action for days.

Baby formula, medications, photographs, warm clothes, nappies, important papers, mementos, pillows, sleeping bags and waterproof plastic bags should be included in an evacuation kit.

Anyone remaining at home during the cyclone should have an evacuation kit as well as fresh batteries for radios and torches, a first aid kit, sturdy gloves, waterproof bags, candles and matches.