GEVGELIJA, Macedonia (AFP) - More than 1,500 mostly Syrian refugees, trapped in no-man's land for three days, entered Macedonia from Greece on Saturday without any attempt by the police to stop them, an AFP reporter said.

Macedonian police had earlier used stun grenades and batons in a bid to stop hundreds of refugees breaking through barbed wire fencing on its southern border with Greece, but in the evening they allowed all the migrants into the country.

Police officers were seen guarding the frontier but not a single person remained in the strip of land between the Greek-Macedonian border where more than 2,000 people, including women and children, had been stuck since Thursday.

The migrants are hoping to cross into Serbia in the north and eventually start a new life in the European Union.

Macedonian police spokesman Ivo Kotevski said police did not want to use force to stop the migrants and refugees, but would continue to control the flow of new arrivals.

"We will continue with reinforced control of the border according to the state of emergency and we will (in future) allow only a limited number of people into the country in accordance with the capacities we have," Kotevski told AFP by phone.

He said no new people would be allowed to enter until the current group had moved on towards the north, "or we will have a humanitarian crisis in Macedonia."

Thousands of refugees and migrants, mostly from Syria, Iraq and Afghanistan, are expected to arrive in the country in the coming days after being ferried to the Greek mainland from the islands.

Macedonia on Thursday declared a state of emergency and sealed its border in a bid to stop the influx, and its officers twice resorted to force to try to prevent people from entering the country.

At least a dozen were slightly injured in clashes with police.