One of the best-known actors remaining in Iran on Sunday strongly backed the protest movement that has rocked the country, vowing to stay in her homeland and pay "any price" for her rights.

Taraneh Alidoosti, well known to international audiences as a regular star in films by Oscar-winning director Asghar Farhadi, said she planned to stop working and instead support the families of those killed or arrested in the crackdown.

"I am the one who stays here and I have no intention of leaving," Alidoosti, 38, wrote in a post on Instagram amid a crackdown that has seen several prominent cultural figures arrested.

She denied having any passport other than an Iranian one or any residence abroad.

"I will stay, I will halt working. I will stand by the families of prisoners and those killed. I will be their advocate," she said.

"I will fight for my home. I will pay any price to stand up for my rights, and most importantly, I believe in what we are building together today," she added.

As a hashtag, she used the protest movement's main slogan: "Woman. Life. Freedom."

Alidoosti is known as a forthright defender of women's rights and wider human rights in Iran. When major protests rocked the country in November 2019, she declared that Iranians were "millions of captives" rather than citizens.

Her best known role was in Farhadi's film "The Salesman", which won best foreign language film at the Oscars in 2017.

But she has been a prominent presence on the Iranian cinema scene since her teens and also starred in the recent acclaimed movie by director Saeed Roustayi "Leila's Brothers" which was shown at this year's Cannes Festival.

Iranian cinema figures were under pressure even before the start of the now seven-week-old protest movement sparked by the death of Mahsa Amini.

Prize-winning directors Mohammad Rasoulof and Jafar Panahi remain in detention after they were arrested earlier this year.