Annan said he expected European nations to contribute troops to a large, more effective international force which would give the Lebanese government time to disarm Hezbollah.
"It is urgent that the international community acts to make a difference on the ground," he said as Israel pounded Lebanon for a seventh day in response to the kidnapping of two soldiers and rocket attacks on northern Israel.
Speaking to reporters after meeting Jose Manuel, president of the European Commission, Annan said: "The proposed UN force would have to be more effective than the current UN interim force in Lebanon which has been unable to keep peace on the Israeli-Lebanese border.
"The force will be larger, the way I see it, much larger than the 2,000-man force we have there. I would expect a force that will have a modified and different concept of operation and with different capabilities."
Annan then called for all European countries to contribute to the force and also appealed to "countries from other regions" to help.
Both Barroso and Javier Solana, the EU foreign policy chief, said they supported the idea and that a number of EU countries were ready to send troops.
The US and Israel say they are doubtful about the idea of such a force, with Washington questioning how much might it would take to restrain Hezbollah, while Israel officials said such a move was premature.
John Bolton, the US ambassador to the United Nations, has also raised a series of questions about how a new force would be more effective than Unifil, and asked who would disarm Hezbollah.
Annan said he would put a package of proposals to the UN Security Council once a fact-finding mission, currently in Israel, reported back to him probably after returning to Lebanon and visiting Syria.
In response to questions, he suggested it was the Lebanese government, not the proposed force, which would eventually have to disarm Hezbollah.