The announcement came after Kuwait's Emir Sheikh Sabah al-Ahmad Al-Sabah, whose country is hosting the talks, met with the two delegations separately and urged them to reach a peaceful solution.
It also came a day after the UN Security Council urged all sides in the negotiations to be constructive.
The two delegations "agreed to an agenda for negotiations which is a framework for discussing security, economic and political issues," UN envoy Ismail Ould Cheikh Ahmed told a press conference.
It states that the rebels must withdraw from seized territories and disarm before talks can progress.
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But Ould Cheikh Ahmed said the UN wants all the main issues to be discussed in parallel by joint committees.
He said no timeframe has been set for the talks which should continue as necessary to achieve a "comprehensive peaceful settlement."
"We don't want to go back to Yemen without a peaceful settlement," Ould Cheikh Ahmed said.
More than 6,800 people have been killed and around 2.8 million displaced since a Saudi-led Arab coalition began operations in March 2015 against the Iran-backed Huthi Shiite rebels who have seized swathes of territory, including the capital Sanaa.
The negotiations represent the best hope in months for a settlement to the conflict.
The 15-member UN Security Council yesterday stressed the importance of agreeing on a "roadmap" to implement security measures including the withdrawal of heavy weapons.
The rebels have insisted that no ceasefire can be established without an end to coalition air strikes and sorties.
The government side wants the rebels to lift the siege on cities, open humanitarian passages and release prisoners.