The system, which reformed into a cyclone over the weekend, is expected to intensify into a category three storm by Wednesday morning.
Queensland Deputy Police Commissioner Bob Gee said Tuesday was the day for people to decide if they were going to stay or leave.
"But that is a voluntary decision," he said.
"It is a very unclear picture in terms of where the cyclone is going to move."
Mr Gee assured residents there would be enough emergency personnel available if the event reached disaster level, despite the fact extra resources have been allocated to the Gold Coast for the Commonwealth Games.
Parts of Queensland hit by Tropical Cyclone Debbie just a year ago are now in the firing line of Tropical Cyclone Iris as it threatens the Whitsunday coast.
Mr Gee advised those travelling to the region to remain alert and re-think their plans.
Premier Annastacia Palaszczuk was updated on the situation as she chaired a meeting of the Queensland Disaster Management Committee on the Gold Coast on Tuesday.
"No matter what community gets impacted we are all here to help," she said.
Iris is located about 290km northeast of Townsville but is continuing to move south along the Queensland coast.
State Emergency Services Minister Craig Crawford said residents in the Mackay and Whitsunday regions could expect to experience heavy rain and high winds over the coming days.
"They'll see very similar effects to what they saw a year ago with TC Debbie, but obviously not as severe," he said in Brisbane on Tuesday.
"We believe it's going to sit around the Whitsunday region for a couple of days and then head further out to sea."
Mr Crawford said Cairns and Townsville appeared to be in the clear, but given the erratic path the system had tracked so far, they were keeping a close watch.
A cyclone warning has been issued for the area between Ayr and Sarina, with gale force winds, heavy rain and flash flooding possible.
A watch zone is in place from Sarina to St Lawrence.
Iris is not expected to affect the opening ceremony of the Commonwealth Games on the Gold Coast on Wednesday nor the associated royal visit by Prince Charles and Duchess of Cornwall.
It's also not predicted to impact Commonwealth Games events being held in Cairns and Townsville, which begin later this week.
