Tunisian police fired teargas on Friday to disperse protesters in the town of Zarzis who were trying to reach the island of Djerba, where leaders of French-speaking countries are to hold a summit this weekend, witnesses said.

Protests have roiled Zarzis, which is connected to Djerba by a long bridge, for weeks over the Tunisian state's response to the death of local people in migrant shipwrecks.

Tunisian President Kais Saied will welcome French President Emmanuel Macron and other leaders in Djerba on Saturday and Sunday after their foreign ministers meet on the island later on Friday in the showpiece event of the Francophonie group.

"We wanted to protest and make our voices heard in Djerba, but the authorities' response was with force and we were suppressed," said Salim Zuraidat, one of the protesters.

Zuraidat is among a group of relatives of people from the Zarzis area who drowned weeks ago in one of the many shipwrecks of migrants seeking to cross the Mediterranean to Europe.

They started protesting in Zarzis over what they saw as a dismissive government approach to the disaster including an initial failure to send boats out to look for bodies and a failure to identify those bodies that were found before burial.

A spokesperson for Tunisia's Interior Ministry said it had no details or immediate comment on Friday's protest or the police response to it.