UN envoy Martin Griffiths flew out of the rebel-held capital Sanaa on Tuesday with a delegation of Huthi insurgents, heading to Sweden for negotiations with the Saudi-backed government.

The four-year-war between the Iran-aligned Huthi rebels and pro-government forces has pushed the country to the brink of famine, with 14 million people facing the threat of starvation according to the UN.

Footage of severely malnourished children, too weak to move, has grabbed the world's attention.

"What we have now is a window of opportunity -- probably the best we have seen in months -- to finally get peace talks started," said Elizabeth Dickinson, senior analyst with the International Crisis Group.

Saudi Arabia, which leads a military coalition backing the Yemeni government, is more inclined to accept calls to end the fighting amid increased global pressure following the murder of journalist Jamal Khashoggi in its Istanbul consulate.

But doubts remain as to whether external pressure is enough to bring both sides to the table "in a serious way", Dickinson told AFP.

- 'Most opportune time' -

UN Secretary General Antonio Guterres said last month that if the war can be ended, "we will be stopping the most tragic humanitarian disaster we are facing in today's world."

In September, peace talks faltered when the Huthis refused to travel to Geneva, accusing the UN of failing to guarantee their delegation's return to Sanaa or secure the evacuation of wounded rebels to Oman.

Negotiations hosted by Kuwait in 2016 broke down after 108 days and left rebel delegates stranded in Oman for three months.

In significant steps towards kickstarting talks in Sweden, 50 wounded rebels were evacuated on Monday for treatment in Oman and a prisoner swap deal was announced.

Neil Partrick, a specialist in Gulf Arab politics, said that now is "the most opportune time to end the fighting" since the 2015 Saudi-led intervention.

Saudi Arabia has been facing intense criticism over the murder of Saudi citizen Khashoggi in October, which Riyadh said was a "rogue" operation.

The killing "has given the US and the UK the opportunity to try to nudge the Saudis into being more serious about what an advantageous end to the fighting might look like for them and their Yemeni allies," Partrick told AFP.

Britain last month presented a draft resolution to the UN Security Council demanding a truce in Yemen, although the United States said a vote on the measure should be put on hold until negotiations are held in Sweden.

Although international pressure on Riyadh may have paved the way for talks and a temporary cessation of hostilities in the key port city of Hodeida, Yemen specialist Franck Mermier cautioned challenges to peace remain.

"It will not force Saudi Arabia to stop the battles without significant military gains on the ground," said Mermier, an anthropologist at France's CNRS research centre.

The Huthis will meanwhile be unwilling to relinquish power "and their concessions will be minimal," he said.

- Collapsing economy -

The coalition's six-month battle to seize Hodeida from the Huthis has been largely suspended, but operations at the port -- the entry point for the majority of aid -- have been reduced drastically according to the UN.

Yemen's finances have been devastated by the conflict, with the World Bank reporting the economy has contracted by around 50 percent since 2015.

Unemployment is running at over 30 percent and inflation is projected at around 42 percent, while the majority of state employees are not paid.

"The situation is catastrophic and harsh... Revenues have dried up... and the riyal's value has deteriorated sharply," Yemeni economist Ahmed Ghaleb told AFP.

In Sanaa, people have been feeling the pinch for some time and are waiting to see whether this round of negotiations will finally bring peace.

"All Yemenis hope for the success of the planned peace talks, but there is a belief that they won't be successful," said resident Abdelrahman al-Bseir.

"If these talks are successful, then they would have been for Syria and other (war-torn) countries," he added.

In Aden, Khaled Fadel was more optimistic and hoped the negotiations would prove successful.

"But they will (only) work if all parties offer concessions," he said.