Several containers exploded Saturday at a key Iranian port, authorities said, causing a major blast and fire, and leaving several people injured.

State media reported a "massive explosion" at Shahid Rajaee, the country's largest commercial port located in Hormozgan province on Iran's southern coast.

"The explosion occurred in a part of the Shahid Rajaee port dock, and we are extinguishing the fire," state TV quoted Esmaeil Malekizadeh, a regional port official, as saying.

Shahid Rajaee, more than 1,000 kilometres (620 miles) south of the capital Tehran, is the most advanced container port in Iran, according to the official IRNA news agency.

It is located 23 kilometres west of Bandar Abbas, the Hormozgan provincial capital, and north of the Strait of Hormuz through which a fifth of world oil output passes.

Footage on state TV showed thick columns of black smoke billowing from the port area where many containers are located.

"Four rapid response teams were dispatched to the scene after the explosion," Head of the Hormozgan Red Crescent Society, Mokhtar Salahshour, told state TV.

Mehrdad Hassanzadeh, head of the province's crisis management authority, told state TV that "the cause of this incident was the explosion of several containers stored in the Shahid Rajaee Port wharf area."

"We are currently evacuating and transporting the injured to nearby medical centres," he added, without specifying the number of casualties.