Thousands of pilgrims travel each May to the El Ghriba synagogue on the island of Djerba to mark a holiday which follows Passover. They usually hold a vibrant festival filled with music and pageantry.
But this year celebrations will be muted because of continued unrest in the country following the overthrow of President Zine al-Abidine Ben Ali in January.
"It's true that we have cancelled all the celebrations planned for this year but the pilgrimage will still take place next Friday at the synagogue," organizer Perez Trabelsi told Reuters.
"People that usually come are scared this year," he said, saying he expected only a few hundred people.
A government source said the pilgrimage would be cancelled completely.
El Ghriba was the site of an al-Qaeda attack in 2002 which killed 21 people. Another synagogue was set on fire by arsonists in the Tunisian city of Ghabes in February.
Mainly Muslim Tunisia has one of the largest Jewish communities in North Africa but until recently attacks have been rare.
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