Sydney CBD gas explosion injures 14

A young child and three people have been taken to hospital after they were injured in a gas main explosion in Sydney's Chinatown district.

At least 200 people were evacuated from the five-storey building in Haymarket when the explosion occurred in the loading dock of the building's food court around 7.40pm on Tuesday.

At least 14 people were treated for lacerations from flying debris and other injuries, a NSW Fire and Rescue spokesman told AAP.

The fire did not spread throughout the building and was contained by sprinklers, he said.

Crews are working with hazmat units to ensure there is no lingering gas in the building, which is expected to be declared safe later on Tuesday night.