Tunisia's Prime Minister Habib Essid faces a vote of no confidence in parliament on Saturday after resisting the president's proposal to help form a new unity government to push through economic reforms.
Essid, a technocrat who came to office less than two years ago, has been under fire for slow progress on a financial reforms package to create growth and jobs, initiatives demanded by Tunisia's multilateral lenders.
President Beji Caid Essebsi has called for a new unity government to overcome political divisions in the ruling coalition of four parties and respond more quickly to economic and security challenges.
Most lawmakers are expected to vote in favour of sacking Essid. Islamist party Ennahda, the largest party in parliament, and Essebsi's secular Nidaa Tounes party, have said they will vote against the premier.
"I never opposed the president's proposal," Essid told lawmakers in parliament. "But it was put forward at a difficult time for the country and has caused the delay in several key projects and laws."
Since its 2011 revolution to oust Zine El Abidine Ben Ali, Tunisia has emerged as a democracy praised as a model for the region. But militant attacks have tested the government and political infighting has slowed economic progress.
Essebsi has said the country needs a more dynamic government ready to take audacious decisions to bring about the liberalisation and cost-cutting required for an overhaul of the North African state's economy.
Three Islamist militant attacks last year - including gun attacks on foreign visitors at a museum and a beach resort - have badly damaged the tourism industry, which makes up around 8 percent of the economy and is a major source of jobs.