Authorities in Greece say more than 1,200 migrants have been detained on the island of Crete and the nearby islet of Gavdos over the past three days, following a surge in arrivals from Libya.

Greece on Friday enforced a three-month freeze on asylum claims from migrants arriving by boat from North Africa, to stem a surge from Libya that the government has called an "invasion".

More than 500 people were transferred to the port of Lavrio near Athens on Thursday after being intercepted south of the island of Crete, as Greece implements emergency measures to address a surge in Mediterranean crossings from Libya.