Austria will supply equipment to help Macedonia keep its border closed and Europe's main migrant route blocked, a German newspaper reported on Wednesday.

Last week, Macedonia closed its border with Greece to migrants. People who tried to cross the border on Tuesday were forced back to Greece, where about 12,000 migrants have been stranded.

"Austria has offered support to Macedonia," Defence Minister Hans Peter Doskozil told the newspaper Die Welt. "The Defence Ministry is currently checking whether we can help with technical gear, such as night vision goggles."

The Balkan route, Europe's main passage for migrants towards more affluent countries to the north, had "to be kept closed at all cost", Doskozil said.

Last year, over 1.5 million migrants arrived in Europe, unleashing fierce political debates across the continent over how to handle the influx.