Greek authorities have transported more than 500 migrants to a port on the mainland in an effort to relieve strain on the island of Crete after 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.