Iran must immediately halt the executions of two women sentenced to death over their support for LGBTQ rights, United Nations experts said Wednesday.

Iranian judicial authorities prosecuted Zahra Sedighi-Hamedani and Elham Chubdar in August and notified them this month that they had been convicted and sentenced to death, the rights' experts said in a statement.

"We strongly condemn the sentencing of Ms. Sedighi-Hamedani and Ms. Chubdar to death and call on authorities to stay their executions and annul their sentences as soon as possible," the experts said.

"Authorities must ensure the health and well-being of both women, and promptly release them from detention."

The experts said that while the judicial decision was not public, they had been informed that the charges concerned speech and actions in support of the human rights of LGBTQ people facing discrimination in Iran.

Homosexuality is banned in Iran, with its penal code explicitly criminalising same-sex sexual behaviour for both men and women.

The experts said they had voiced their concerns to the Iranian government that the women may have been arbitrarily detained, ill-treated, and prosecuted on the basis of sexual orientation or gender identity, "including criminalisation of LGBT people whose human rights they were supporting".

They said they had received no response from Tehran.

The UN rights office said earlier this month that it was "deeply concerned" by the death sentences and lamented that they had been convicted "on the vague and broadly formulated charge of 'corruption on Earth', following a trial which reportedly lacked due process and fair trial guarantees".

The experts who issued a joint statement Wednesday included the special rapporteurs on the rights situation in Iran, arbitrary executions, protecting freedom of expression, human rights defenders and violence against women.

They also included members of the working groups on arbitrary detention, discrimination against women and enforced disappearances.

The independent experts do not speak for the UN but report their findings to it.

The intervention comes in the midst of protests in Iran that erupted nearly two weeks ago over the death of a young woman in custody.

Dozens of people have been killed since nightly demonstrations erupted after Mahsa Amini, a 22-year-old Kurdish woman, died after being arrested in Tehran for allegedly breaching the Islamic republic's strict rules on hijab headscarves and modest clothing.

Officials said Monday they had made more than 1,200 arrests, including of activists, lawyers and journalists.