An archived image shows demonstrators at a Tunis rally protesting the lack of reforms since Ben Ali's ousting [EPA]

Five Tunisians have tried to hang themselves after failing a competition to become teachers in the impoverished western Kasserine region, witnesses and media reports said.

The men climbed an improvised scaffold outside a branch of the education ministry and tied rope nooses around their necks, witness Rachid Jabbari told the AFP news agency.

One of the men, aged 43 - the age limit for entering Tunisian civil service - sustained a head wound before the group were rescued by a crowd of bystanders on Friday. They were taken to hospital, where the governor of Kasserine visited them, the official TAP news agency reported.

The other four were later released from hospital, reported Radio Mosaique FM.

"It was an act of desperation," Jabbari said. "This first competition since the revolution was their last chance."

Jabbari said the five, all in their 40s and unemployed, had been refused jobs in the competitions organised under Zine El Abidine Ben Ali's ousted administration, despite having the appropriate qualifications.

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The suicide by immolation of street vendor Mohamed Bouazizi is credited with triggering the revolt that resulted in Ben Ali's overthrow on January 14.

Since then, unemployment has risen from 14 per cent to 19 per cent at the end of July, according to official figures - a rise attributed to the arrival on the jobs market of some 80,000 new graduates, and the return home of more than 30,000 Tunisians who fled the conflict in neighbouring Libya.

Despite efforts of the transitional government to preserve jobs and create new ones, some 10,000 have been lost and another 80,000 are threatened, AFP reported.

On October 23, the country will elect a Constituent Assembly tasked with drafting a new constitution.