About 25,000 people living in low-lying Mackay are being urged to evacuate the area, with fears Cyclone Debbie will bring a devastating tidal surge to the region.
Debbie is expected to hit the coast as a Category 4 topical cyclone just south of Bowen at 9am on Tuesday, ahead of high tide at 9.44am.
Police Commissioner Ian Stewart told a briefing on Monday afternoon forecasters were predicting a storm surge inundation ranging between 0.8 and 2.5 metres for the Mackay area.
"We are asking people that can move out of those low-lying areas that are depicted on the local maps on the council website to move now," he said.
"Don't wait until tomorrow because you will not be able to move probably past midnight tonight."
He said there were about 25,000 residents in the affected zones but it was possible many had already left.
Those able to get on the road should do so "as soon as humanly possible" and get at least as far south as Rockhampton, Mr Stewart said.
Emergency services would do everything they could to assist locals but he urged people to take care of their neighbours and help each other out.
"That's the Queensland (and) Australian way," Mr Stewart said.
Drivers also needed to take care, with the impending cyclone and storm surge likely to put a "huge stress" on the state's roads, he warned.
"This is a fairly big undertaking (and) we have a limited amount of time to do this," he said.
The 15 evacuation centres in Mackay were only for those who have no other option, he added.
Queensland Premier Annastacia Palaszczuk said authorities were "very concerned" about the possible tidal surge in Mackay.
"It's very clear that the time for people to move is now," she said, encouraging locals to listen carefully to official advice.
Emergency alerts for a storm surge have been issued by Mackay Regional Council for the areas of North Pioneer, South Pioneer, Louisa Creek, Armstrong's Beach, Dunrock, Ball Bay, Freshwater Point, Grasstree, Half Tide and Seaforth.
