Ocean carriers are expanding their capacity with more ships which may not be needed.

Shipping consultant firm Drewry warns a current focus on ordering new liners capable of carrying 8,000 to 10,000 twenty foot equivalent units (teu) may prove excessive.

It states 55 vessels of an average 8,600 teu will be delivered by the end of the year, increasing capacity in the sector by 18 per cent - a figure it argues is well above global growth. This will be followed by 40 more in 2014 and 45 in 2015, each increasing available space by 11.6 per cent year-on-year.

A spokesperson for Drewry said: "Ocean carriers have returned to ordering vessels between 8,000 and 10,000 teu in large numbers, suggesting that either overcapacity is brewing ahead, or unusual service developments are in the pipeline."

Additionally, 44 vessels averaging around 14,600 teu are due next year, which could replace smaller carriers.

It suggests this development may be a bid to compete with the anticipated P3 alliance, a cooperative effort between Maersk, Mediterranean Shipping Company and CMA CGM.

Maersk, for example, already offers some of the world's largest cargo ships, capable of transporting 18,000 teu.