The men are believed to have been suffocated due to possible lack of oxygen.

Local media have identified the ship as the 46,500-dwt Saga Frontier (built 2007), owned by Japan’s Nippon Yusen Kaisha (NYK).

The foreman, a driver and an assistant were from the area around Belgium’s Beveren, with long working experience.

Paddy Crumlin, president of the International Transport Workers’ Federation, said: “Antwerp is a port where health and safety is taken very seriously, and, like the three men’s trade unions, we are confident that a full investigation will take place into what happened and how any resulting lessons can be implemented.

“Dock work is dangerous work and everyone involved must always do everything possible to minimise the risks.”