A trickle of refugees have been allowed to cross the border from Greece into Macedonia - the first for two days following clashes earlier this week.
Macedonia briefly opened the border crossing overnight, letting around 170 people cross, Greek Police said.
However some 10,000 people remain camped at the crossing, awaiting their turn.
It comes after clashes broke out on Monday as hundreds attempted to storm the border crossing.
Video report by ITV News Europe Editor James Mates
The refugee crisis is in danger of turning into a humanitarian disaster, the UN has warned.
Many migrants are living in crowded camps in poor conditions as wire fencing prevents them from crossing from Greece into Macedonia.
The border camp is only designed to house 1,500 people but is currently home to 9,500.
Gemma Gillie, from aid agency Medecins Sans Frontieres told ITV News: "We don't have enough [supplies] for 9,500 people.
"These people are not having their basic humanitarian needs met, or it is very close to the line, and that's why, for us, this is a crisis."
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