India's busiest port, which was shut after a collision of two cargo ships off Mumbai's coast, partially resumed operations, a port official told Reuters.

"We are plying about 6-8 ships in JNPT and Bombay Port Trust. It is possible only during high tide and day time," said an official who did not wish to be identified because he is not authorised to talk to the media.

Environment Minister Jairam Ramesh said normal traffic would be resume this week.

The collision, which triggered an oil slick, has hit operations at the Mumbai port and the neighbouring Jawaharlal Nehru Port after about 300 containers fell into the shipping channel used by the ports.

Only some containers have been secured and work is underway to remove all the containers that fell into the sea, the official said.

Port officials will meet later in the day to decide when the port operations can resume fully, he added. (Reuters)