They were part of around 7,000 refugees whose journey to the European Union had been temporarily blocked last week when Macedonia declared a state of emergency and shut its borders for three days to halt the huge influx of people mostly fleeing war in Syria, AFP reports.
Authorities reopened the crossing after chaotic scenes involving police lobbing stun greandes at the migrants trying to break through the border.
The UN's refugee agency said on Tuesday it expected the number of refugees moving through Macedonia to double from around 1,500 per day to 3,000 per day, many of them women and children.
It warned that the situation was also worsening on the shores of Greece and Italy, where the number of Mediterranean Sea crossings was now approaching 300,000.
Since the beginning of the year, more than 2,370 have drowned in the Mediterranean, already exceeding the death toll for the whole of 2014, according to the International Organization for Migration