Tunis - Tunisia's new constitution will not be adopted before February 2013, the head of the drafting committee said on Tuesday, after earlier announcing that it would be delayed until April.
"I believe that in all reality there can be no final reading of the constitution before February 2013," Habib Kheder, who is also an MP and member of the ruling Islamist party Ennahda, told Tunisian radio station Mosaique FM.
"There can be no hastening," he added.
Kheder had said on Monday that the final draft of the new national charter would be voted on in parliament "at the end of April".
The government had previously insisted it would meet an October deadline for ratifying the constitution, in order to hold planned general elections in March next year.
Kheder has declined to comment on whether he now expects the elections to take place on schedule, saying on Monday that was "the responsibility of the government".
But the new hitch to the democratic transition looks likely to compound the political uncertainties facing Tunisia, which has been rocked by social unrest in recent months, including strikes, protests and clashes with the police.
On Tuesday hundreds of protesters demonstrated against Tunisia's ruling Islamist party during a general strike in Sidi Bouzid, hub of the 2011 uprising, an AFP journalist reported.
Opposition and civil society groups accuse Ennahda of increasingly authoritarian and Islamist tendencies.
They are also growing more critical of the government's failure to bolster the economy and improve living standards, 17 months after the revolution that overthrew veteran strongman Zine El Abidine Ben Ali and touched off the Arab Spring.
"Can the country handle another such delay? Can Tunisia's fragile economy withstand another delay?" asked opposition MP Issam Chebbi on Monday.
"We will demand a law that fixes a date for the elections," said the spokesperson for the Republican Party, when contacted by AFP, adding that "the longer the transition lasts, the more the chaos will spread."
Kheder said the commission would meet in early September to discuss a "comprehensive timetable" for drafting the new constitution, which has been heavily delayed due to an apparent deadlock over certain key issues.
The Islamists in the ruling coalition are pushing for a pure parliamentary system, while the other parties want important powers to remain in the hands of the president.
President Moncef Marzouki belongs to the secular centre-left Congress for the Republic, one of Ennahda's coalition partners.