Man arrested in search after woman shot dead

A woman has been shot dead and a man injured in an alleged attack that sparked an emergency declaration and manhunt in the Queensland city of Mackay.

Police arrested a 31-year-old man outside a fast-food restaurant hours after the "absolutely shocking" incident resulted in a number of streets being locked down.

District Superintendent Graeme Paine said a 34-year-old woman had driven into Robb Place in South Mackay on Wednesday afternoon when a 31-year-old man approached and fired into the vehicle, striking the woman.

Two young teenagers who were also in the vehicle fled to a nearby residence, after which a 66-year-old man came to the woman's aid, Supt Paine told reporters.

The gunman allegedly shot him in the chest.

The woman died from her gunshot wound, while the 66-year-old was taken to hospital in a serious but stable condition.

Police were called to the scene after 4.30pm and made an emergency declaration and put an exclusion zone in place at 5.20pm.

Patrols later found a suspect vehicle and about 7.45pm arrested the 31-year-old man outside a fast-food restaurant about 2km away from the scene of the shooting.

He was assisting police on Wednesday night.

"I don't have any details at this stage in relation to any sort of motive or reasons behind what's occurred," Supt Paine said.

Police did not know if the woman and two men were known to each other but believed they "resided in close proximity to each other".

Supt Paine said police were examining a number of scenes.

The shootings were "an absolutely shocking thing" for the teens to have experienced.

"They obviously were very fearful and they've gone and sought help and that help was provided and unfortunately that male who also provided help has been injured, so an absolutely tragic situation," Supt Paine said.

The emergency declaration was revoked late on Wednesday around Robb Place, Paradise Street, Archibald Street, Kindermar Street and Denton Street.