LEIPZIG, Germany - One of the key challenges facing the shipping industry today is from within itself, as increasingly bigger vessels may outpace the development of port and landside infrastructure needed to support them.

While there has been a doubling in the size of ships every eight years, ports are built for about 30 years so there is a "timing difference", said PSA International's group chief executive Tan Chong Meng on Thursday.

Mr Tan noted that "mega mega-ships", such as the Maersk Triple E class which can carry over 18,000 TEUs (twenty-foot equivalent units), have appeared in the past few years, and the number of such vessels may hit about 80 in 2018.

"We need to be able to cope with them (mega ships) and actually ensure that we are not breaking down the resilience of the rest of the trade system," he said at the International Transport Forum summit held in Germany.

Mr Tan, who was one of seven panellists invited to speak on the theme of enhancing transport system resilience and sustainability, said policy makers need to study whether their countries' ports are robust enough for the next 20 to 30 years, while imagining the size of the shipping fleets in the future.

While shipping trade developed cities in the past, this is not the case anymore, when countries' gross domestic product becomes diversified and ports move away from cities. However, when this happens there must be appropriate transport and freight corridors to support the move, he said.

"The question...to ask ourselves is, does each of us have a port and city urban masterplan that is good enough for the next 20 years? It takes about five to eight years to upsize ships (to) double, but it takes cities a decades, two decades, sometimes longer," he added.