The United Nations yesterday rebuked donors for not doing enough to help millions of Syrian refugees in the region as well as host countries, saying "massive" aid is needed.

"These countries received about three million registered and unregistered Syrian refugees... the truth is that this enormous impact is not being fully recognised by the international community," UN High Commissioner for Refugees Antonio Guterres said at a meeting of senior diplomats and officials from Egypt, Jordan, Iraq, Lebanon and Turkey.

"Let me be very clear, there has been very little support," he said at northern Jordan's Zaatari refugee camp, which is home to more than 100,000 Syrians.

"There must be massive support from the international community at the level of government budgets and development projects related to education, health, water and infrastructure."