The ship operated by the 2M alliance of Danish shipping company Maersk Line and Switzerland's MSC is one of two 350-plus-metre container ships to dock in Koper in recent days.

On Sunday, a cargo ship operated by the Ocean 3 alliance of France's CMA-CGM, China's CSCL and UASC, a joint venture of six countries from the Gulf, arrived in Koper.

Luka Koper has launched direct container connections with Asia with the two shipping alliances, complementing its existing partnership with Taiwanese shipping company Evergreen in providing direct Europe-to-Asia services.

"Both new lines have Koper as the first port of call in the Adriatic, which is especially important for business partners who are hoping for the shortest transit times," Luka Koper wrote in the statement.

With transshipment of 674,000 containers, the port of Koper ranked as the largest container port in the Adriatic for a fourth year running in 2014.

The port said it had plans to deepen its seabed by another metre this year as part of broader expansion that will also see it extend its pier and invest a total of EUR 200m in new infrastructure by 2020 to increase container capacity from 850,000 a year to 1.15m a year.

The company stressed that container cargo shipping is one of the fastest growing sectors in the world, growing by an average of 10% a year.

While the ships which have docked at the port in recent days are the biggest ever to stop in Koper, they still lag behind the record-breaking Maersk triple E class ships, 400-metre behemoths which rank as the biggest container ships currently sailing the world's seas.