(Reuters) - Libya's legislative assembly gathered on Sunday to vote on a law banning officials who worked for Muammar Gaddafi from the new administration, a step that could potentially force out the prime minister and other senior officials.
The wording has been wrangled over for months and Sunday's vote has been prompted by the actions of heavily armed groups who have taken control of two government ministries and say they will not leave until the legislation is passed.
"It's a very unfair and extreme law, but we need to put national interests first in order to solve the crisis," said Tawfiq Breik, spokesman for the liberal National Forces Alliance (NFA) bloc.
On Sunday, more than a dozen vehicles mounted with anti-aircraft weapons and machine guns remained parked outside the Justice Ministry, and the Foreign Ministry has been similarly encircled for the past week.
One of the men stationed in front of the Justice Ministry, who said the group came from different areas close to the capital Tripoli, said they would not leave until the prime minister had been forced from office.
"We have been asking them to deal with Gaddafi's friends for a year," he said.
Diplomats in Tripoli said the vote would be meaningless because it was being held under duress, while a human rights group has called on congress to reject the latest draft.
"This law is far too vague - potentially barring anyone who ever worked for the authorities during the four decades of Gaddafi's rule" said Sarah Leah Whitson, a Human Rights Watch director in the region.
The latest draft states that anyone who worked for Gaddafi, including the prime minister who worked at a Libyan embassy before defecting more than 30 years ago, would be excluded from the administration.
The leader of the congress, Libya's equivalent of parliament, his deputy and around 40 other members could also be barred should that version be passed.
The vote was expected to take place in the afternoon, but the timing was unclear.
The cabinet and Libya's official armed forces are so weak that swathes of the oil-producing desert country remain outside central government control.
The gunmen who played a pivotal role in the revolt that toppled Gaddafi have never left the capital and are more visible than Libya's military.
Soldiers stationed in the main square to protect a pro-government protest on Friday have now left, although a number of army vehicles remained outside a central bank building nearby.
(Reporting by Jessica Donati and Ghaithb Shenne; editing by Mike Collett-White)