The incident at the Hindustan Shipyard Ltd site occurred when a new crane collapsed during a weight-bearing trial, Suresh Babu, a deputy commissioner of police, told Reuters.
Rescue workers were trying to cut the crane and remove its pieces, Babu said. He added that if anybody was trapped alive under the crane, they would only be found once it was lifted.
There was no immediate comment from Hindustan Shipyard. A company official said senior executives were in a meeting over the accident.