The container shipping unit of Danish shipping and oil group A.P. Moller-Maersk has entered into an alliance with its two biggest rivals MSC Mediterranean Shipping Company S.A. and CMA CGM to improve operations and services.

The companies, the three biggest container shipping operators in the world measured on capacity, aim to start operations in the second quarter of 2014, depending on regulatory approvals, Maersk Line said in a statement.

The alliance, the P3, will be an independently operated network consisting of 255 vessels with a total capacity of 2.6 million Twenty Foot Equivalent Units (TEU), serving the Asia-Europe, Transpacific, and Transatlantic (North Europe and Mediterranean) trades, the company said.

Maersk Line will contribute with more than 100 vessels.

"Declining volume growth and over-capacity in recent years have underlined the need to improve operations and efficiency in the industry," Maersk Line said in the statement.

The three lines will continue to have fully independent sales, marketing and customer service functions.

The alliance will allow each of the lines to offer more weekly sailings in the combined network than they do individually. In addition, the network will offer more direct ports of call, Maersk Line said.