The collapse of a flyover bridge being built at Mumbai's main airport killed three people and injured another six, Indian police said on Thursday.

"A large slab fell suddenly late last night, trapping several people underneath it," Uttam Korekar, a senior police inspector, told AFP at the site of the accident.

"Most of them were labourers," he added.

The injured were admitted to nearby hospitals.

The flyover is part of a major construction project for a new terminal at the Chhatrapati Shivaji International Airport.