At least 11 people were killed and 35 injured on Saturday in a fire at a shopping mall in Pakistan's commercial capital of Karachi, officials said.

More than 60 people were inside the mall when the fire broke out on the fourth floor of the six-storey building in the southern port city.

"Our rescue workers have taken 11 dead bodies to hospitals so far," said Shahid Hussain, a spokesman for the Chippa welfare organisation, which runs a rescue service.

He said 35 people were injured, with seven of them in serious condition.

"At least 40 people have been rescued," he added.

Shabbir Ali, a provincial health ministry spokesperson confirmed the death toll and number of injured persons.

Hussain said the fire was started by a generator short circuit and spread to engulf two floors of the building.

Poor safety laws and building codes as well as lax enforcement mean fires in large buildings are frequent in Pakistan.

In 2012, at least 250 labourers died at a garment factory in Baldia Town, in western Karachi, when a fire engulfed the facility.

The building had no fire escape.(AFP)