A video showing an Iranian policeman shoving a woman protesting against mandatory headscarves off her makeshift podium in a busy Tehran street sparked criticism on social media on Friday.

The video of the solitary female demonstrator was apparently shot on Enghelab (Revolution) Street, where a woman was first detained in December after standing with her head uncovered waving a scarf on a stick.

Since then several dozen Iranian women have published photos of themselves in the street or parks, their heads uncovered, waving their scarves in an act of defiance.

The woman in the video is seen standing on a street cabinet with her arms raised in the air, her long blond hair worn in a high ponytail.

Asked by two policemen to get down, she replies calmly: “Tell me what my offence is and I'll get down.”

“Disturbing public order,” one of them says.

A crowd then forms and starts clapping.

In the second part of the video, apparently shot on a cellphone, one of the policemen steps up to the same height as the woman and shoves her off her podium, to the indignation of onlookers.

“Where are the human rights?” a male voice asks.

Lawyer and human rights activist Nasrin Sotoudeh wrote on Facebook that the policeman broke the law because “no man has the right to treat a woman like this”.

Twitter users also reacted with dismay.

“Breaking the law while in law enforcement uniform is our problem in Iran,” one tweeted.

“The same police force that makes the girl fall over in Enghelab Street is the one responsible for ensuring the security and viability of the elections,” said another.

Since December around 30 women have been arrested in Tehran for defying a requirement under Iran's legal code to wear a headscarf.