Tens of thousands of women in a southern Indian state have formed a 620km human chain in support of a court order overturning a partial ban on women entering one of Hinduism's holiest temples.

The "Women's Wall" rally on Tuesday was backed by the communist government in Kerala state, where the court order on the Sabarimala temple had triggered weeks of protests by opponents and supporters of the ban.

Government employees took part in the demonstration, while schools were given a half-day and university exams delayed so that students could join the protest, the Press Trust of India news agency reported.

A government statement issued before the event predicted five million women would participate in the protest.

Kerala has become the venue of an angry showdown between Hindu traditionalists and supporters of September's Supreme Court ruling, which ended a centuries-old ban on women of menstrual age entering the temple.

The top court said the ban infringed on the right to worship. Since then, several women have tried to reach the hilltop shrine, but were forced back by opposing activists.

Opponents of the court ruling, which include Prime Minister Narendra Modi's nationalist Bharatiya Janata Party, say that the ban was essential to the rites related to the temple's chief deity Ayyappan, considered eternally celibate.

In some Hindu communities, menstruating women are regarded as unclean, leading to restrictions and in a few cases outright bans from entering certain places.

Police have clashed with devotees supporting the ban and have arrested more than 2,000 people.

Elizabeth, a school teacher and a member of the left-backed Kerala State Teachers Association, told The Indian Express that women's right to pray was being "violated by male-dominated protests at Sabarimala".

"Those who have faith in the deity must be able to enter and pray," she said.

A 23-year-old IT worker who also participated in the rally added: "We have to fight against blind traditions and superstitions."

Hundreds of thousands of Hindus - men, young girls and elderly women - trek to the temple for an annual festival that usually falls around the end of the year.

The Supreme Court is set to hear challenges to its landmark ruling from January 22.