On Friday alone, just over 130 people were rescued in two operations carried out by ships from the EU border agency Frontex.
On Saturday, a passing oil tanker was asked to rescue another 30 or so people from a small boat.
Those rescued are being taken to reception centres set up on the islands of Lesbos and Samos, from where they may be taken on to the Greek mainland.
Crete and the nearby small island of Gavdos lie along a sea route used by migrants setting off from Libya in boats in an attempt to reach Europe.
