Syria Peace talks, which were scheduled to open Monday, will instead begin in Geneva on Friday and last for six months, the UN’s Syria envoy Staffan de Mistura said.

Syria Peace talks, which were scheduled to open Monday, will instead begin in Geneva on Friday and last for six months, the UN's Syria envoy Staffan de Mistura said.

De Mistura told reporters that the start date was pushed back because of a "stalemate" over the makeup of the delegations, but that the invitations to the participants were expected to be sent out on Tuesday.

"We are going to aim at proximity talks starting on the 29th and ongoing for six months" De Mistura said, adding that the first round was expected to last between two to three weeks.

"There will be no opening ceremony," the UN envoy said.

Securing a ceasefire and space to deliver humanitarian aide to suffering Syrians will be among the first priorities, he added.

"We are all feeling... the time has come to at least try hard to at least produce an outcome," De Mistura told reporters.

The talks will mark the first time the warring sides will take part in negotiations since January 2014, when de Mistura's predecessor Lakhdar Brahimi hosted high-level but fruitless meetings in the Swiss cities of Montreux and Geneva, a round of talks known as Geneva II.