The expansion is the first step towards a goal of handling 8 million 20-foot containers per year by 2013, placing it among the top 10 port complexes in the world by current standards, said Etienne Rocher, Managing Director of APM Terminals Tangier.
The Tanger-Med port allows the Maersk subsidiary to keep expanding container handling operations on the Strait of Gibraltar after its Spanish Algeciras complex nearby reached saturation point.
Some 200 ships pass through the Strait every day.
Industry executives expect global container traffic to double by 2014.
For the Moroccan government, Tanger-Med is the focal point of attempts to revive a long-neglected northern region and spur foreign businesses to shift operations to a chain of free trade zones linked to the port by new motorways and rail lines.
French carmaker Renault RENO.PA said last year it would build Africa's biggest car factory near Tanger-Med, capable of producing up to 400,000 vehicles a year.
For now the local Moroccan market for container import and export represents only 600,000 20-foot-equivalent units (TEU) a year, said Rocher. He said 95 percent of the port's activity in the next 10 to 15 years would focus on transferring containers arriving from smaller ports onto the world's biggest container ships for travel on to Asia and the Americas.
APM Terminals is now dealing mostly with Europe, Asia and Africa traffic but expects to begin handling traffic from South America, the Middle East and West Mediterranean feeder services in coming weeks, said Rocher.
"This should allow us to reach 1 million containers over this 12-month period. That is ahead of our initial targets," Rocher said late on Thursday during a press visit to the port.
APM has invested 145 million euros in the first phase, Tanger-Med 1, and says that is enough to allow it to reach a capacity of 1.4 million TEU by 2010.
It expects heavier investment in the larger Tangier-Med 2, under construction nearby, which will have a quayside 2.8 kilometres long compared to 1.6 kilometres for the first port.
"With the addition of Tanger-Med 2 it will be the biggest port compex on the African continent by far," said Rocher.
APM Terminals has a 30-year concession to operate the Tangier port, which can handle ships with a draught of 18 metres.
Rocher said the company was eyeing a tender to operate a third container terminal at Morocco's Atlantic port of Casablanca.