Rival Syrian camps were due in Geneva on Wednesday (February 22nd) for UN-brokered talks to end the six-year conflict, AFP reported.
Regime negotiators and opposition delegations were expected to arrive in the Swiss city a day before talks resume following a 10-month hiatus.
The opposition quit the last round in protest at escalating bloodshed and on Thursday warned that ceasefire violations were once again a major hurdle.
"The obstacles are clear and one of them is that there is no advance in consolidating the ceasefire," said Yehya Aridi, an adviser to the opposition High Negotiations Committee.
UN mediator Staffan de Mistura's office on Tuesday said the talks remain focused on "political transition".
Forty human rights organisations have called for the talks to focus on ending the rights violations that have characterised the war.
"One of the main goals of the Geneva talks should be putting an end to the violations against Syrians who have faced bombing, chemical attacks, starvation, illegal detention and more horrors," said Lama Fakih of Human Rights Watch in a joint statement.