Insurance firm Beazley said it would lead a "marine war consortium" to provide the extra coverage via Lloyd's, the leading insurance market.

"The consortium is designed to support the maritime sector with additional war insurance capacity as it deals with a complex and evolving situation in and around the Strait of Hormuz," it said.

The facility "will be offered to vessels and their cargoes whilst transiting the Strait of Hormuz; coverage will be in line with Beazley's risk appetite and in compliance with all global sanctions", it added.

The arrangement will help "in keeping global trade moving", Beazley chief executive Adrian Cox said in the statement.

The war has driven up payments for the insurance that underpins the world freight industry, analysts told AFP.

Iranian forces have closed off the strait to all but a trickle of ships since the war erupted on February 28 with US and Israeli strikes on Iran.

About 30 vessels have reported being hit or targeted in the area, according to the the UK Maritime Trade Operations Centre.

Executives in London, the world's biggest shipping insurance market, have insisted that captains are avoiding the route to protect their crews, not because insurance was unavailable.

"Safety concerns, not insurance availability, (are) driving reduced vessel traffic," the Lloyd's Market Association, a ship insurance trade body, said in a report.

US Treasury Secretary Scott Bessent said in late March that a US shipping insurance initiative to boost Hormuz crossings would begin operating soon.