DUBAI (BLOOMBERG, REUTERS) - A fire caused by an explosion on a container ship at Dubai's Jebel Ali Port is now under control and no causalities have been reported, authorities said.

The massive blast lit up the city and occurred just after midnight local time, the Government of Dubai Media Office (DMO).

Video on social media showed fire and debris from the blast scattered around the port.

Jebel Ali Port is the largest in the Middle East and a key centre for trade in the United Arab Emirates.

The cause of the incident is being investigated, DMO director-general Mona Al Marri said on the Saudi-owned Al Arabiya television channel.

The explosion was a "normal accident" in a container holding flammable material, Al Marri said.

Dubai Police told the network the fire may have been caused by "friction or high temperature," and added that no radioactive materials were on board.

Witnesses in residential areas from 15km to 22km from Jebel Ali had heard the blast.

A Dubai Civil Defence team worked to put out the blaze.

"We are taking all necessary measures to ensure the normal movement of ships in the port continues without any disruption," Dubai Media Office said, citing Jebel Ali Port authorities.

It said the ship, which was not identified, was preparing to dock at a berth "away from the port's main shipping line".

Al Arabiya cited the Dubai government as saying the ship's crew had been evacuated in time.

The port is operated by DP World, which wasn't immediately available for further comment when contacted by Bloomberg. It handled 13.5 million shipping containers in 2020, down 4.4 per cent year-on-year due to the Covid-19 pandemic.

DMO posted footage of water being pumped to douse flames and debris at the scene.

There appeared to be normal movement of vehicles in and out of the port while civil defence vehicles continued to arrive at around 2100 GMT (5am on Thursday, Singapore time), Reuters witnesses said.