Yemen's Parliament on Wednesday urged the government to halt negotiations with the UN until it reviews a "supposed" Houthi withdrawal from the Red Sea port city of Hodeidah.
The UN special envoy for Yemen, Martin Griffiths, brokered a ceasefire agreement and troop withdrawal from the ports of Hodeidah, Al Salef and Ras Isa during peace talks in Sweden in December.
But the actions of the Houthi rebels have hindered the agreement.
“The military forces of Ansar Allah have now left the three ports,” Mr Griffiths told the UN Security Council last week, referring to the Houthis. “This will allow the UN to play a leading role in supporting the Yemen Red Sea ports in management and inspections at the ports.”
But the government has accused the rebels of disguising their fighters in coastguard and police uniforms to keep control of the ports.
Officials reserved the right to verify last week's withdrawal, dismissing the pull-out as a "show" meant to "misinform the international community".
"What is disappointing is that the so-called recent withdrawal has been endorsed by the UN envoy Martin Griffiths which is blatantly challenging UN Resolution 2216 and the Sweden agreement," the parliament said in a statement on Wednesday.
“The approach that the UN envoy has taken will not achieve peace but will prolong the war and the suffering of the Yemeni people.”
Hodeidah is the point of entry for most of Yemen's commercial goods and aid supplies and an end to violence is considered vital to speed up delivery of much-needed food and medical supplies.
Yemeni officials said Mr Griffiths had lost his ability to be a neutral arbitrator when he endorsed the rebels' withdrawal.
"The UN envoy has requested to meet with the government in Riyadh, but officials have said there is no need," a Yemeni government official told The National.
“He is not welcome here. If he decides to come he will only meet with Saudi officials.”
There is ongoing public frustration with Mr Griffiths after his briefing to the UN Security Council. Many believe he simply "lied to keep the momentum going for the peace agreement he brokered", a Yemeni activist told The National.
"There is a trend not just at the level of parliament, but in all corridors of the government and political forces," Askar Zael, Yemen's military attaché to Turkey, a member of the government's delegation to Sweden and member of parliament, told The National. "The parliament is authorised to issue such statements as it is a legitimate entity of the Yemeni state and a state institution."
Hamzah Al Kamaly, Yemen's Deputy Youth Minister and a member of the government delegation to Sweden, said President Abdrabu Mansour Hadi must "kick Martin Griffiths out as he is biased and no longer a balanced mediator".
But a government official told The National the parliament's statement would not affect the government's interaction with the UN.
Despite the recent setbacks, the international body urged all parties to co-operate with Mr Griffiths.
A spokesman for UN Secretary General Antonio Guterres said: “We are following with great concern the hardening rhetoric in Yemen in recent days. The Secretary General urges the Yemeni parties to work with his envoy Martin Griffiths.”