Massive Queensland blaze under control

A massive fire that gutted four shopping outlets in north Queensland has been brought under control.

Emergency services received reports of a fire in a shopping centre on Greenfield Boulevard, Mackay, at 11.45am (local time) on Saturday.

The Department of Community Safety (DCS) says at 3pm (local time) the main fire, which destroyed most of the Toys R Us, Clark Rubber and Autobarn stores, had been put out and firefighters were hosing down remanent flames.

No one was injured.

A public safety order is still in place because of police concerns about toxic smoke from burning chemicals in some of the shops.

A nearby shop worker, who did not want to be named, said witnesses saw four teenagers being arrested in the carpark.

"They (the teenagers) were in our shop this morning, we hunted them out. They were being horrible in here," she told AAP.

"Officers have put those young people in a paddy wagon."

Police couldn't confirm whether any arrests had been made, but the DCS confirmed a fire investigator would be brought in to work out how the blaze started.

Drivers are being warned to expect long delays on the Bruce Highway, which is next to the shopping centre.

-AAP