The EU anti-piracy mission off the coast of Somalia is facing a shortage of ships as budget cuts are limiting the ability to deploy military assets, the EU's top military officer said Wednesday.

General Hakan Syren, chairman of the EU Military Committee, said the Atalanta operation requires a minimum of four to six warships to patrol the coast but that it would fall "below the red line" in December.

"It is really a problem," Syren said, adding that the mission would again have enough ships in March while the commander was "constantly working" on new ways to work around the issue.

"We have faced this before," he told a news conference after a meeting of military chiefs from the EU's 27 states, which focused on the Horn of Africa.

"I can imagine that there are many different reasons for this, but one is of course economy and the budget cuts," the Swedish general said.

Defence budgets have not been spared as governments across Europe slash spending to contain a debt crisis threatening to plunge the continent into a new recession.

The revolutions that swept across Europe's southern flank could have also affected their ability to contribute warships to the piracy mission, he said.

"When it comes to this kind of assets, I can imagine that member states have felt insecure about the situation in the Mediterranean Sea connected to the Arab Spring and the Libyan crisis," he said.

Spain, France and Germany are the main contributors to the mission, with Italy, The Netherlands and Belgium also taking part in the operation which has been extended until the end of next year.

The operation could count on around 10 warships when it was launched in 2008, but the average has come down to around six or seven vessels to patrol an area 10 times the size of Germany.

The size of the force fluctuates according to the monsoon season, which can curb pirate activity.