BEIRUT (Reuters) - A United Nations body has called for the immediate release of prominent Iranian women's rights activist Bahareh Hedayat and has expressed concern for her health in a report published on Wednesday by a human rights group.

Until her arrest in 2009 Hedayat had been involved in projects calling for gender equality and had reported on cases of sexual violence against female students at universities. She has spent some of her time at Evin prison in solitary confinement.

"The deprivation of liberty of Bahareh Hedayat was arbitrary," the U.N. Working Group on Arbitrary Detention said in its report, compiled in May after a request from the New York-based International Campaign for Human Rights in Iran (ICHRI).

The report said Hedayat, who was also arrested and released multiple times from 2006, should be compensated for her time spent in detention.

Hedayat was convicted in 2010 on charges of insulting Iran's Supreme Leader and president and acting against national security.

The ICHRI said Hedayat should have been released in 2015 after serving five years.

"It is high time for this injustice to end. After almost seven years of unlawful imprisonment, the Iranian authorities should release her immediately," said Hadi Ghaemi, the ICHRI's executive director, in a statement.

The Iranian judiciary could not be reached for comment on the case.

(Reporting By Babak Dehghanpisheh; Editing by Gareth Jones)