Dozens of demonstrators bared all in a bid to defy officers as protests erupted near the famous Obelisk monument in Buenos Aires.
They were joined by hundreds of fully clothed protesters under the slogan "our breasts should not be censored".
Some activists painted "censor this" across their chests after whipping off their bras.
Demonstrator Grace Prounesti Piquet, 33, said: "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."
Last month officers descended onto a popular holiday beach where three women were sunbathing topless.
The trio refused to put their tops back on during the bizarre stand-off with police.
They said officers threatened to arrest them and call in reinforcement forcing the friends to leave.
Police had initially been called by tourists who were said to have been offended by the nudity.
But a row between beachgoers and police soon broke out - with around 20 officers called to the disturbance.
Although the law regarding topless sunbathing in Argentina remains unclear, police cited a national criminal code article prohibiting "obscene displays" to justify asking the women to leave the beach.
However at least one judge ruled after the incident that going topless was not a crime.
The incident has sparked weeks of demonstrations around the country as women protest against the ban, saying it proves social inequality between genders.