"I have spoken to MD, CSL and asked him to provide all necessary medical support to victims and to initiate immediate enquiry with the help of concerned agencies," Gadkari said.
According to a shipping ministry official, at least five people have been killed in the blast.
Earlier, a CSL spokesperson said a fire had broken out on a ship under repair in the premises, killing three people.
Eleven persons trapped inside the ship were evacuated and rushed to hospital, the spokesperson said.