The United Nations deputy chief said Thursday he hoped new talks aimed at ending Yemen's seven-month war could start this month despite a "deep distrust" between the warring parties.

UN peace envoy for Yemen Ismail Ould Cheikh Ahmed has proposed for a new round of talks to begin "within the next few weeks", UN Deputy Secretary-General Jan Eliasson told reporters in Geneva.

"We have suggested that they start before the end of this month," said Eliasson, who has just returned from visits to Saudi Arabia, the United Arab Emirates and Iran.

"We very much hope that these talks will take place, and that that will be combined with a reduction of violence and cessation of hostilities," he said.

Some 4,500 civilians have been killed since a Saudi-led coalition in March launched a bombing campaign against Iran-backed Huthi rebels, who had overrun Yemen's capital Sanaa and seized territory as far south as Aden with help from renegade troops loyal to former president Ali Abdullah Saleh.

Saudi Arabia and the UAE have contributed the bulk of forces who rushed to the defence of the country's internationally recognised president, Abedrabbo Mansour Hadi, allowing his forces to regain control of Aden and several southern provinces.

Eliasson said leaders in both Saudi Arabia and the UAE had expressed "a desire, a will to move to the political phase as soon as possible," adding that he had asked them "to make that case very strongly to the Hadi government."

He acknowledged though "the deep mistrust that exists between the key actors, not least between Saudi Arabia and UAE on one side and Iran on the other."

A first attempt to hold peace talks in Geneva in June between the pro-government forces and Huthi rebels collapsed without the warring parties even sitting down in the same room.

And last month, Hadi's government backed away from UN-sponsored talks that were to be held in Oman, insisting the rebels first agree to UN resolution 2216 passed in April demanding their withdrawal from territory they have seized since overrunning the capital in September 2013.

But Eliasson pointed out that the Huthis had sent a letter to the UN agreeing to abide by the resolution, which "was a positive move."

"We hope that the Hadi government will also come to the talks now, and that both sides will come to the talks without preconditions."

He stressed the urgency of starting the talks, pointing out that "Al Qaeda has increased its influence and their territorial control because of this war."

"We see the cost in terms of human losses, and we see the ... gains of terrorism on the ground as a reason to go ahead," Eliasson said.

"I would just appeal to both sides and to all sides that can influence the parties that they really now should not miss this opportunity," he said.