The UN Human Rights Council will hold a special session to investigate the massacre of 108 people in the Syrian town of Houla.
The UN says most of the victims were summarily executed in the town on on Friday. The victims included 49 children and 34 women.
The act has caused outrage worldwide, prompting Western countries to expel Syrian ambassadors and officials.
The United States, Qatar, Turkey and the European Union led the push for the special session, to be held in New York on Friday.
It will be the fourth time Syria has been summoned before the UN body since unrest broke out in the country in March last year.
On Tuesday, the US, Britain, France, Germany, Spain, Italy, the Netherlands, Australia and Canada expelled the diplomats and officials.
British Foreign Secretary William Hague said Syria must choose, as time is running out for United Nations-Arab League special envoy Kofi Annan's peace plan.
Australian Foreign Minister Bob Carr said it was the best way to send a message to the regime.
Two diplomats are to be expelled from Australia who are also accredited to New Zealand.
New Zealand Foreign Affairs Minister Murray McCully has expressed his full support for the expulsions.
Syrian president Bashar al-Assad said "terrorists" were to blame for the violence on Friday.
Mr Assad told Kofi Annan, who is visiting the capital Damascus, that terrorists had stepped up their operations across Syria, including killing and kidnapping.
More clashes are being reported in the city of Homs and in the suburbs of Damascus on Wednesday.