Six of the world’s 10 most at-risk ports are on the US coast of the Gulf of Mexico, with exposure to hurricanes the main factor in their rankings, according to catastrophe modeller RMS.

Using new modelling techniques, RMS has ranked world ports based on potential for insurance losses over a 500-year period from earthquake, wind and storm surge.

The US port of Plaquemines in Louisiana ranks third, with estimated potential losses of $US1.5 billion ($1.95 billion).

Nearby New Orleans is fifth with estimated losses at $US1 billion ($1.3 billion).

The Mississippi port of Pascagoula is sixth, followed by Beaumont, Texas at seventh, Baton Rouge, Louisiana at eighth and Houston, Texas ninth.

Nagoya in Japan is the most at-risk port, with marine cargo potential losses estimated at $US2.3 billion ($2.99 billion).

Guangzhou in China is next with potential losses of $US2 billion ($2.6 billion).

Bremerhaven in Germany ranked fourth, with Le Havre, France, the 10th-most at risk.

RMS Director Product Management Chris Folkman says a port’s size and its catastrophe loss potential are not strongly correlated.

“For example, while China may be king for volume of container traffic, our study found that many smaller US ports rank more highly for risk – largely due to hurricanes.

“Our analysis proves what we’ve long suspected: that outdated techniques and incomplete data have obscured many high-risk locations.

“The industry needs to cease its guessing game when determining catastrophe risk and port accumulations.”

RMS marine risk experts considered cargo type, precise storage location, storage type and dwell time – the amount of time a ship spends in port – in their assessments.

They say catastrophic risk exposures for marine insurers have grown with the increasing size of ships and port capacities. Many river ports are now inaccessible to larger vessels, forcing shippers to rely on seaports, which are more vulnerable to hurricanes, typhoons and storm surge.

In addition, many ports are built on landfill, amplifying their vulnerability to earthquake risk.