The main challenger to Tunisia's veteran president in a forthcoming election accused the government on Wednesday of scuppering his campaign by censoring his manifesto.

Ahmed Brahim said supporters were unable to hold rallies, hand out leaflets or display posters because his message was deemed to be hostile to the state and the ruling party.

The race for the Oct. 25 presidential and legislative poll began on Sunday.

"It makes no sense to stop our party doing anything," Brahim told Reuters. "Our election statement is being withheld without any clear legal justification."

President Zine al-Abidine Ben Ali has led the north African country of 10 million, a staunch Western ally, since 1987 when doctors declared his predecessor Habib Bourguiba to be senile and unfit to rule.

Subsequent elections have returned Ben Ali to power with massive majorities and in 2002 a referendum allowed him to theoretically extend his rule until 2014.

The government has said repeatedly it is committed to increasing civil liberties and Ben Ali promised on Sunday to expand democracy and reduce unemployment if he won another five-year term.

Rights groups and some political opponents say Tunisia's government is authoritarian with a veneer of pluralism. They say it stifles free speech and beats and jails opponents, something the government denies.

The offending passages of Brahim's manifesto call for a "break with authoritarian, unequal distribution of wealth" and denounce a "one-party mentality," according to a source in Brahim's party Ettajdid (Renewal).

Interior Ministry officials were not available for comment.

Brahim, 68, is the candidate of a group of small, non-recognised leftist and independent parties known collectively as the Democratic Initiative. His own party holds three seats in Parliament.

Ben Ali's other challengers -- Mohamed Bouchiha of the Wehda Chaabia (Popular Union) and Ahmed Inoubli of Wehdawi (Unionist) parties are both seen as close to the ruling elite.

Brahim said the government was squandering an opportunity to improve its image by ensuring the election is transparent and fair.

"They are supposed to portray a positive image of the country in this period," he said. "This heavy censorship and further erosion of freedom is a cause of concern and puzzlement."

Reuters