The UN envoy has met delegates of Yemen's warring parties separately in a bid to restart peace negotiations after a protest walkout by the government, the United Nations said on Tuesday.

The government delegation quit on Sunday in protest at the rebels' seizure of one of the few loyalist army bases in the northern mountains in a blow to the peace talks launched on April 21.

It came just a day after the rival delegations held their first face-to-face meetings in a bid to end a conflict that killed more than 6,400 people and displaced some 2.8 million since March last year.

UN envoy Ismail Ould Cheikh Ahmed met both government and rebel delegations late on Monday in a bid to find a swift resolution to the dispute over the rebels' seizure of the Al-Amaliqa base on Saturday despite an April 11 ceasefire.

Commanders appear to have put up no resistance as the rebels overran the base in Amran province, nearly all of which is under their control, tribal and military sources said.

Foreign Minister Abdulmalek al-Mikhlafi, who heads the government delegation, told Sky News Arabia there would be no more direct or indirect talks with the rebels until they withdrew from the camp and gave guarantees there would be no further breaches of the ceasefire.

Despite a Saudi-led military intervention in support of the government launched in March last year, the rebels and their allies still control the capital, as well as much of the northern and central mountains and Red Sea coast.