The video conference is scheduled for Friday, and the French president's office has said it aims to bring together "non-belligerent countries" ready to contribute to a "purely defensive mission".

The strait, a key route for global oil and gas shipments, has been largely closed since the start of the US-Israeli war against Iran.

Merz said that Germany was willing in principle to take part in such a mission, but also planned to "discuss the question of the participation of the United States armed forces" at Friday's talks.

"There are good arguments in favour of it," he told a press conference in Berlin alongside his Irish counterpart.

He stressed that he would not "prejudge the outcome" of the talks, to be co-chaired by French President Emmanuel Macron and British Prime Minister Keir Starmer.

Merz added any German participation in a mission to secure the strait could happen only after "at the very least a provisional ceasefire" as well as approval by the government in Berlin and parliament.

"We are still a long way from that," he added.

A ceasefire officially came into force in the war on April 8.

But it remains fragile, with the US navy launching a blockade of Iranian ports this week after talks between US and Iranian officials in Pakistan failed to reach a deal to end the war.