The Libyan peace process has taken a backwards step with the country's democratically elected House of Representatives passing a vote of no confidence in its internationally recognised, UN-backed government.

Libya has been engulfed in chaos since the ousting of 40-year dictator Muammar Gaddafi in 2011, but the country's UN backed peace process hopes to remedy a two-year-long political crisis that erupted when militias forced the House of Representatives to flee the capital.

Since August 2014, expanding anarchy in Libya has provided a breeding ground for the Islamic State (Isis) and allowed the black market trade in guns, petrol and people to flourish.

The Government of National Accord was the result of seemingly interminable UN-backed talks, which created a unity government under Fayez Serraj, now installed in Tripoli.

The spokesman for the House of Representatives Abdullah Ablahig said 61 lawmakers voted against the government, 39 abstained and one voted to support it, with enough members to reach a quorum. Questions have been raised over the validity of the vote. One pro-government lawmaker told the Associated Press his parliamentary colleagues had not been made aware of the vote.

While it is not clear what happens next, and whether the Serraj government can make any claim to legitimacy, the vote is a blow to the international community's efforts to purge IS from Libya.

The international community has said it will only cooperate with a unity government in Libya to achieve strategic aims. US airstrikes have hit Isis positions in the Isis stronghold of Sirte, with British and US special forces deployed on the ground.

Militias, predominantly from the costal Libyan town of Misrata and fighting under the auspices of the Government of National Accord, claim to have all but liberated Sirte. At one point there were thousands of Isis militants in the town, according to UN and US estimates. It was believed to be a fall-back position for Isis as its territory was eroded in the Levant.