Foreign ministers of the Syria "contact group" were to hold their first high-level meeting on Monday in Cairo, Egypt's foreign ministry said.
The top diplomats of "Egypt, Turkey and Iran will meet at the foreign ministry to discuss developments in Syria on the political and humanitarian fronts," the ministry said in a statement.
Saudi Arabia is also a member of the group, but it was not immediately clear who would represent the kingdom at the talks.
The gathering of the "contact group" on Syria -- an initiative by President Mohamed Morsi -- follows preparatory talks a week ago in the Egyptian capital held by lower-ranking officials from the four countries' foreign ministries.
International peace envoy for Syria Lakhdar Brahimi, who paid a four-day visit to Damascus during which he met President Bashar al-Assad and opposition members, was to join the meeting, an Arab diplomat said.
Iranian Foreign Minister Ali Akbar Salehi was also to meet separately with Morsi during his visit to Cairo, Iran's official news agency IRNA reported.
Salehi told Iran's ISNA news agency before leaving Tehran on Monday that Tehran would be setting out its "clear" position on its ally Syria.
"We are very hopeful given that four important countries of the region are gathered to discuss one of the sensitive issues of the region," he was quoted as saying.
The very fact the meeting was being held was "a positive step," he said, "and we hope that its results will correspond to the interests of all the people of the region, and to peace and stability."
Salehi reaffirmed that Iran was looking to expand the group to include allies Iraq and Venezuela.
In Cairo, a diplomatic source speaking to the state-owned daily Al-Ahram said that the group was "open to any positive contribution from other parties in the future."
Brahimi this month took over as peace envoy from former UN chief Kofi Annan, who stepped down amid discord and acrimony in the UN Security Council over how to tackle the conflict in Syria.
The death toll from the 18-month-old conflict has risen to more than 27,000 people, according to a tally of activists' counts. The United Nations puts the toll at 20,000.
More than 250,000 Syrians have fled the violence to neighbouring countries.