The tragedy unfolded as thousands of worshippers tried to reach the Kyeik Hne pagoda, which lies on a rocky outcrop around three kilometres (two miles) off the coast near the town of Thanbyuzayat in southern Mon state.

Local officials said some died when they tried to cross the poorly marked causeway, which is only around four metres wide, while the tide was too high.

“We normally allow the people to come at 6:30 am but they would not listen to us and started trying to walk across too early,” local official Nai Sahai Eain told AFP.

More drowned later when they were jostled from the crowded walkway into the sea.

Ko Kyaw Thu, an emergency responder from Thanbyuzayat, told AFP that 15 bodies had been taken to hospital and three people were still missing.

Local resident Nai Wona told AFP the causeway was not marked out clearly enough, making it hard to navigate.