Tunisia's Islamist party Ennahda, which holds the second largest number of seats in parliament, said on Sunday it would reject a government proposed last week by Prime Minister-designate Habib Essid, complicating his cabinet's ratification.
A leftist block also said it was opposed to the planned administration, underlining the tough task Essid faces in tackling essential economic reforms, even if his cabinet manages to win a confirmation vote in parliament expected on Tuesday.
Tunisia has been praised for its recent run of free elections, new constitution and politics of compromise between secular and Islamist leaders four years after an uprising overthrew autocrat Zine El-Abidine Ben Ali.
But Essid courted controversy last week when he selected ministers from secular Nidaa Tounes, the leading party in parliament, and other smaller partners, while shunning Ennahda.
"We decided not to approve this government because it does not represent all the political classes and it breaks with the consensual way we have worked recently," Ennahda leader Sahbi Atig told Reuters after a party meeting on Sunday.
Representatives from the leftist Popular Front said they would also reject the new cabinet partly because it contained former officials from Ben Ali's regime, some of whom they said were suspected of corruption in the past.
Abd el Aziz Kotti, a Nidaa Tounes lawmaker, said there were also divisions within his own party, with some opposed to the new government, fearing it would not be strong enough.
Since its 2011 uprising, Tunisian politics has often been dominated by compromises between secular and Islamist leaders to keep democratisation on track after a series of deadlocks threatened to overturn its transition.
Nidaa Tounes won a parliamentary election in October and party leader Beji Caid Essebsi, a former Ben Ali official, also won the presidency in a second-round run off.
In the 217-seat parliament, Nidaa Tounes holds 86 seats and has some backing from the liberal, secular UPL party, which has 16 seats. But that leaves Essid still short of the 109 majority they need to ratify the cabinet.
They may look for backing from Afek Tounes party, nominal allies with eight seats, but its delegates walked out of negotiations to form the government. Ennahda has 69 seats in the assembly and the Popular Front has 15 lawmakers.
Ennahda had said it was open to a unity government with Nidaa Tounes to improve stability. The new government is set to crack down on militants and tackle sensitive cuts in public spending and subsidies demanded by international lenders.
Nidaa Tounes itself is an coalition of former Ben Ali officials, leftists and independents. Its hardliners were opposed to joining up with Ennahda, which they blame for unrest during the first Islamist-led government after 2011.
"Now it is not sure they will get the support to pass this government," said local political analyst Kahled Abid. "Even if they pass, it may be in a weak position to take on the political, economic and security challenges."
