Argentinian women are going semi-nude in a protest for the right to sunbathe topless.

Police, as seen in a heated exchange captured on film involving dozens of people, asked three young women lying on a southern Buenos Aires beach to put their shirts back on.

Dozens of topless women and hundreds of fully-clothed people, in a demonstration that was copied elsewhere in the country, have been protesting at the Buenos Aires’ Obelisk monument this week.

It remains unclear what, if any, the law is surrounding nudity on the South American country’s beaches.

It followed protests over gender equality and a 16-year-old girl's rape last year Marcos Brindicci/Reuters (Marcos Brindicci/Reuters)

Police during the January incident cited a national criminal code article prohibiting “obscene displays”, but at least one judge has since said that going topless is not a crime.

Some protestors told journalists the incident was just the latest example of grave social inequality between men and women in the traditionally Catholic nation.

It followed the “Not One Less” protests late last year, in which tens of thousands of Argentines protested gender-related violence after the rape and killing of 16-year-old Lucia Perez.

There were 235 “femicides”, a term written into Argentine law, in 2015.

“In many places, when a woman reports gender violence, they don't listen, but when a woman shows her breasts they send so many police,” said Grace Prounesti Piquet, a 33-year-old photographer.

She had the words “the breast is not a crime” painted in pink on her back.

“It's a shame.”

One protester had “censor this” written on her chest, and another: “We are not going to ask you for permission.”

A sign read: “The only breasts that bother them are the ones that aren't for sale.”