Greece's government says it expects a growing number of stranded migrants and asylum seekers after neighbor Macedonia further restricted border access at the weekend.
Ioannis Mouzalas, a deputy minister for migration, on Monday said the European Union was failing to deal with unilateral actions and an "outburst of scare-mongering'' from individual member states.
Macedonia imposed the restrictions at the weekend after Austria imposed a cap on transit and asylum applications.
The action left thousands of migrants stranded in Greece, at the border and the port of Piraeus, near Athens, where regular private services to the border were suspended.
Nearly 100,000 migrants and refugees have traveled to Greek islands from nearby Turkey so far this year.