Lebanese activists protested Sunday at a beach in the coastal city of Sidon after a woman said she was harassed there over her allegedly indecent bathing suit, an AFP correspondent said.

Defying a municipality ban on their demonstration, dozens of protesters, mostly women, gathered briefly in the Sunni Muslim-majority conservative city, the correspondent said.

"We have all come to support women's right to be in public spaces, whether in a bikini or a burkini," said Diana Moukalled, a journalist and women's rights activist.

"Public spaces don't just belong to certain people as a function of their beliefs, but to everyone. It's a constitutional right," she told AFP.

In last week's incident, a group of conservative religious Muslims reportedly assailed a bather and her husband at the public beach in Sidon, accusing them of not respecting local norms due to the woman's attire.

The incident sparked a wave of solidarity on social media, with some women posing in bathing suits with the hashtag #Sidon.

Others instead praised the conservative intervention.

The Sidon municipality on Saturday had banned both the women's protest and a planned counter-demonstration that had been called "in favor of modesty, virtue and against nudity".

A group of conservative Muslims later arrived to break up the pro-swimwear protest and held prayers at the beach as security forces deployed to the area.

Sheikh Houssam Ilani decried the "provocations" of demonstrators flouting the protest ban.

A sign at the beach entry indicates alcohol is prohibited and requests "decent attire".

Lebanese law does not ban bathing suits in public, but women in the conservative coastal city often prefer to attend private beaches while wearing such dress.