Police in Benin fired tear gas to break up a protest over the cost of living called by trade unions and they arrested several senior union figures on Saturday, witnesses and union officials said.

Armed police blocked access to the labour council in the commercial capital Cotonou, surrounding the area where the demonstration was meant to take place and turning away journalists.

Some protesters nonetheless gathered nearby, carrying signs and wearing union T-shirts. Police used tear gas to disperse them.

Moudassirou Bachabi, who heads the General Confederation of Workers of Benin (CGTB), and Anselme Amoussou, head of union CSA-Benin, were arrested alongside 16 other demonstrators, according to CGTB deputy general secretary Anita Bossoukpe.

Appolinaire Affewe, the head of a confederation of unions, also said Amoussou, Bachabi and others had been arrested.

The police could not be reached for comment.

"I have been here since 6 am and the entrance was already blocked," Bossoukpe told Reuters.

"We are all hungry. I received my salary on the 22nd, at this moment I don't even have 500 CFA francs ($0.82) and I have to get through the month, which has barely started."

Clemence Akinocho, another demonstrator, said the cost of food staples was too high in the West African country.

"We didn't come here to fight or to cause trouble, but we came and saw that the police outnumbered us," she said.

The guaranteed minimum salary in Benin is 52,000 CFA francs ($85) per month, up from 40,000 CFA francs ($65) in January 2023.

But the prices of fuel and food products including corn, gari flour, beans and cowpeas, have risen in recent months.

The International Monetary Fund said this month that incomes in sub-Saharan Africa are falling further behind the rest of the world amid a "tepid" economic recovery.

Benin launched a sovereign dollar bond earlier this year.