BRISBANE - A dust storm has engulfed southern Queensland, causing traffic delays, raising health concerns and cancelling horse racing.

Traffic has slowed on major routes across Brisbane, Ipswich and the Gold Coast.

Ipswich councillor Paul Tully described it as the worst dust storm in a decade.

Drivers in central Brisbane have begun to drive with lights on as the atmosphere in the city turns orange.

A Brisbane Airport spokeswoman said the airport remained open at noon AEST.

She said airport management expected a call from air traffic control on Wednesday afternoon that will close the airport when the dust thickens.

People with respiratory conditions need to be cautious about the dust haze now affecting much of the south of Queensland, the Department of Health said.

Acting executive director of Population Health Queensland, Sophie Dwyer, says only people with respiratory conditions need to be cautious.

"For most people, the only risk they'd face is that the dust may irritate the eyes, nose and throat," Ms Dwyer said.

"Dust might pose a slight risk though to some people by increasing the symptoms of some respiratory diseases like asthma, chronic bronchitis and emphysema, or people with heart disease."

She said if dust was causing any problems, people should keep their windows and doors closed.

"People with lung or heart conditions are advised to limit their exertion while the dust haze lasts," she said.

"Anyone with these conditions should remain indoors as much as possible, continue to use usual medication and seek medical attention if their symptoms worsen."

Horse racing at Eagle Farm has been abandoned over fears for the safety of jockeys in the poor visibility.

- AAP