Frontex expressed concern about the 'extremely unstable' situation in North Africa and said it would increase the size of its Poseidon Operation in the Aegean to include the southern Mediterranean island of Crete, which is close to Libya.
Portugal has reportedly contributed a helicopter and Romania has sent vessels to assist with sea patrols.
Earlier this month the European Union said its team of 200 border guards will remain on Greece's northeastern frontier with Turkey on a permanent basis to patrol one of the main points of entry for illegal migrants into the EU.
Frontex's statistics show that its mission in the northern region of Evros has resulted in a significant drop in illegal arrivals since October.
An estimated 5,281 immigrants entered Greece illegally via the Turkish land border since the beginning of 2011, compared to 8,054 in November and December. The number of migrants arrested this month was 1,383, compared to 2,266 in January.
Greece said about 128,000 migrants arrived in the country illegally in 2010, the highest for any EU nation.
Athens is considering using floating prisons and old army bases to house undocumented migrants. The government has also announced plans to build a 12.5-kilometre fence along the section of Greece's northeastern border with Turkey, but the plan has met with opposition from human rights groups.
