US Federal Maritime Commissioner Richard Lidinsky, who voted in favour for the G6 Alliance but against the P3, says the P3 will hinder the US, European Union and China in protecting their maritime interests.

"The last thing needed is this device designed solely to fill the largest ships of the controlling carrier at the expense of the world's maritime architecture," he told Lloyd's List.

Mr Lidinsky said the P3 would allow Maersk, when coupled with existing discussion agreements, to deploy its assets along with those MSC and CMA CGM to dominate vessel competition and narrow shipper options.

The commissioner said he supported G6 Alliance plans to extend to the transatlantic and Asia-US west coast trade lanes because the group of shipping lines and its structure made it a "true alliance.

"From the organisational chart, multi-diverse membership, rotating chairmen, vessel-sharing agreement terms and flexible operational procedures, it is well-equipped to serve in a fair and efficient manner," he said.

The expansion plans of the G6, which groups together APL, Hapag-Lloyd, Hyundai Merchant Marine, MOL, NYK and OOCL, were unanimously approved by all five FMC commissioners last week.