Alireza Delkhosh said crews from two vessels -- 32 men from the IRIS Dena, which was torpedoed by a US submarine, and 219 from the IRIS Bushehr, which was given safe harbour in Sri Lanka -- wanted to return home.

"We are talking, and we are following this issue with the Sri Lankan government," Delkhosh said in a press conference broadcast on local networks, but which was not open to international media.

"I do hope that we can solve this problem as soon as possible", he added, saying that they were being treated well but wanted to leave.

"Their only worry is that they are separated from their families," Delkhosh said.

There was no immediate reaction from Sri Lankan authorities to Iran's request.

IRIS Dena was attacked just south of Sri Lanka on March 4, and the ambassador said that 104 sailors were killed, many of them cadets, as well as a music band.

That raises the death toll from 84, based on the recovery of bodies by Sri Lanka's navy. Those bodies have since been flown back to Iran.

Sri Lanka's President Anura Kumara Dissanayake has said that the island provided protection to the Bushehr crew in line with the 1907 Hague Convention, which requires a neutral state to hold combatants of a belligerent state until hostilities end.

Dissanayake on Friday said he had denied permission for US warplanes to use ground facilities in Sri Lanka in order to maintain Sri Lanka's neutrality.

A third Iranian ship, IRIS Lavan, with 183 crew members, sought shelter in India's Kochi port.

Sri Lanka meanwhile has raised fuel prices by more than a third since the start of the Middle East war and has taken several energy-saving measures, including a four-day working week.

The Iranian envoy said Sri Lanka's crude oil supplies would face no issue passing through the Strait of Hormuz.

"Sri Lanka is our friendly country... the Hormuz Strait is not closed to our friendly country's vessels," he said.

"If Sri Lanka demands oil, or any other necessary goods, Iran will supply and provide these goods to Sri Lanka. We don't want to see Sri Lanka in trouble."

Sri Lanka imports all its oil requirements, and the country's only refinery is geared to handle Iranian light crude.