Imprisoned activist Narges Mohammadi has won the Nobel Peace Prize for fighting the oppression of women in Iran.

“This prize is first and foremost a recognition of the very important work of a whole movement in Iran with its undisputed leader, Nargis Mohammadi," said Berit Reiss-Andersen on Friday, the chair of the Norwegian Nobel Committee who announced the prize in Oslo.

"The impact of the prize is not for the Nobel committee to decide upon. We hope that it is an encouragement to continue the work in whichever form this movement finds to be fitting.”

Mohammadi, 51, was behind bars for the recent nationwide protests over the death of 22-year-old Mahsa Amini, who died in police custody.

That sparked nationwide protests in the country, during which more than 500 people were killed, and over 22,000 others were arrested.

Mohammadi's family said the prize is a "historic and profound moment for Iran's fight for freedom" but regretted that she could not share this "extraordinary moment".

Her family said on her official Instagram page, which they maintain while she is behind bars, that the honour belongs to all Iranians, "especially the courageous women and girls of Iran who have captivated the world with their bravery in fighting for freedom and equality".

Release for ceremony

Reiss-Andersen said Mohammadi has been imprisoned 13 times and convicted five times. In total, she has been sentenced to 31 years in prison.

She is the vice president of the Defenders of Human Rights Centre founded by Iranian human rights lawyer Shirin Ebadi, herself a Nobel Peace Prize laureate in 2003

The Norwegian Nobel Committee said it hoped Iran would release the jailed laureate so she could attend the prize ceremony in December.

"If the Iranian authorities make the right decision, they will release her. So she can be present to receive this honour, which is what we primarily hope for," Reiss-Andersen said.

She is the 19th woman to win the Nobel Peace Prize and the second Iranian woman, after Ebadi.