Two people have been taken to hospital suffering from smoke inhalation after a car caught fire in the underground car park of a Central Coast shopping centre.

It's believed the two people taken to Gosford Hospital for treatment were not in the car at the time but were exposed to the smoke, an ambulance spokeswoman said.

Firefighters were called to Gosford Imperial Shopping Centre just after 12pm (AEDT) on Friday.

A car had burst into flames in the underground car park, a spokesman from NSW Fire Service told AAP.

About 150 people were evacuated from the centre.

"We heard the fire alarms go and you could smell the smoke as we headed towards the evacuation point," a local shop employee, who did not wish to be identified, told AAP.

"The younger kids, those aged between six and seven, seemed really upset."

The worker said a number of people complained of headaches.

Staff and customers were later allowed to return to the centre.

The cause of the fire is unknown.