CAIRO (Reuters) - Egyptian women's rights advocate Azza Soliman was freed on bail late on Wednesday after being accused by an investigating judge of establishing an illegal entity and receiving foreign funding to harm Egypt, her foundation and fellow activists said.

Soliman, founder of the Center for Egyptian Women's Legal Assistance (CEWLA), was freed after paying a 20,000 pound ($1,000) bond, the organisation announced on Twitter. She had been detained by police earlier in the day.

There was no immediate comment from the Interior Ministry. Soliman did not immediately respond to requests for comment.

Egyptian human rights defenders say they face the worst government clampdown in their history, with active members and groups accused of fomenting unrest during the 2011 uprising that ended Hosni Mubarak's 30 years in power.

Several non-governmental organisations (NGOs), most involved in rights work, are embroiled in the long-running investigation, accused of receiving foreign funds to destabilise the country.

Fellow activists who attended proceedings said Soliman was accused of tax evasion, establishing an illegal entity and receiving foreign funds to harm Egypt.

In September, a court froze the assets of five prominent human rights activists and three NGOs on similar grounds, paving the way to a criminal trial that could lead to life sentences.

NGOs say they have felt exposed since late 2011, when authorities raided 17 pro-democracy and rights groups.

In 2013, a court ordered the closure of several foreign groups, including U.S.-based Freedom House, and gave jail sentences to 43 NGO staff including 15 Americans who fled.

A case against dozens of Egyptian NGOs and lawyers was never closed but was largely dormant until this year.

Soliman was one of a number of activists, lawyers and journalists banned from leaving Egypt in the last month alone.

She said last week that she was turned back on Nov. 19 at Cairo airport. Soliman later discovered that her assets and those of her group had been frozen.

The escalation comes amid moves to restrict the activities of civil society.

In November, parliament passed a law to regulate NGOs, which rights groups say effectively bans their work and makes it harder for development groups and charities to operate.

The bill bans domestic and foreign groups from political activities or doing anything that harms national security, public order, public morals or public health - a means, critics say, to stifle dissent.

Parliamentarians say safeguards national security.

($1 = 17.8000 Egyptian pounds)

(Reporting by Lin Noueihed; Editing by Giles Elgood)