SINGAPORE - Due to rising sea levels, vessels passing under the Sentosa cable car system will have to meet tighter height restrictions.

Transport Minister Khaw Boon Wan announced on Facebook that vessels entering Cruise Bay must not exceed 50m in height - down from 52m previously. This new ruling comes into effect on Wednesday (July 1).

Cruise Bay is a body of water between Singapore Cruise Centre and Sentosa.

The cable car system connecting the mainland to Sentosa came into operation in February 1974 with a maximum height clearance for vessels set at 56.5m, even though the cableway was built to have a minimum clearance of 60m.

While the previous height limit for vessels was deemed an adequate safety margin, rising sea levels - combined with possible freak tides - may compromise the margin.

"Rising sea levels is a huge challenge for many countries," Mr Khaw wrote.

"To ensure the continued safety of vessels that call at our port, we have lowered the vessel height limit at Cruise Bay from 52m to 50m to ensure sufficient clearance from the Sentosa cable car system."

The decision was made by the Maritime and Port Authority of Singapore (MPA) and the Singapore Cruise Centre, in conjunction with experts in structural analysis, design and climate change.

Mr Khaw, who is retiring from politics, said the MPA will deploy video analytics and laser detectors to enforce the new height limit.

"These measures are necessary to strengthen navigational safety in our waters," he noted.

The MPA said vessels exceeding 50m in height have been calling and will continue to call at the new Marina Bay Cruise Centre.

In 1983, the derrick of an oil drillship struck the Sentosa cableway, causing two cable cars to dislodge and plunge into the sea. Seven people were killed in the incident.

The vessel with its derrick was 69m tall.