Hundreds of tankers are waiting to return to the Strait of Hormuz so that the waterway can once again become a conduit for one-fifth of the world’s oil and gas.

But the shaky ceasefire struck between the United States and Iran has not coaxed the tankers back – and even if it holds, other obstacles have to be overcome for shipping traffic to return to normal.

Iran has kept a stranglehold on the strait throughout the war by laying mines and attacking vessels.

As part of the ceasefire, Iran’s foreign minister said, the country will allow “safe passage” for ships through the strait, but he added that the vessels would have to coordinate with Iran’s armed forces and that passages would be subject to “technical limitations”.

Only four vessels travelled through the strait on April 8, according to S&P Global Market Intelligence, down from an average of nine a day over the previous five days. And shipping analysts said there were no signs of large-scale positioning or queuing to go through the strait.

The fragility of the ceasefire – Iran said on April 8 that Israel’s attacks on targets in Lebanon had violated the agreement – was the main reason ships were holding back, shipping industry participants said.

“It’s too unstable for anyone to commit,” said Mr Oscar Seikaly, chief executive of NSI Insurance Group, a maritime insurance brokerage.

First, shipping analysts say, there has to be confidence that the ceasefire will hold. And then there has to be a declaration from Iran that it will not attack vessels.

“Iran must clarify that the strait is open for safe passage. Otherwise, vessels should not be expected to sail through the way they were doing prior to the war,” said Ms Noam Raydan, a senior fello...