A Coptic Christian teacher in an Egyptian primary school will stand trial after colleagues and the parents of students accused her of insulting Islam and evangelising, a judicial source said on Tuesday.

The trial of Dimyana Ubeid Abdel Nour will begin on May 21, the judicial source said. She has been freed on bail of 20,000 Egyptian pounds ($2,900) ahead of the hearing.

According to London-based rights watchdog Amnesty International, the complaints arose after some students alleged the teacher in the southern city of Luxor said she "loved Father Shenuda", the late Coptic Pope Shenuda III.

She was also alleged to have "touched her knee or her stomach when she spoke about the Prophet Mohammed in class," Amnesty said in a statement that demanded her release.

A judicial source said a complaint signed by some of her colleagues and parents of her students accused her of insulting Islam and proselytising to fourth grade students.

"It is not a crime to speak one's mind on a religion, whether it is their own or that of someone else," said Hassiba Hadj Sahraoui, Amnesty's Middle East and North Africa deputy director.

"Any laws barring such speech violate freedom of expression, and are in breach of Egypt's international obligations under the International Covenant on Civil and Political Rights," she said.

Copts are estimated to comprise up to 10 percent of Egypt's population of 83 million. They complain of discrimination and have been targets of sectarian attacks.

Egypt's laws forbid insults against recognised religions. A court sentenced a Christian last December to three years in prison for posting online segments of an anti-Muslim movie.

A Cairo court is trying a firebrand Islamist preacher on charges of insulting religion after he tore up a copy of the Bible during a protest.

In Egypt, citizens can accuse others of insulting religion or other offences before prosecutors or courts, which occasionally take up the cases.

One such complaint has set off an investigation into a prominent television satirist, Bassem Youssef, who pokes fun at hardline clerics. He is accused of insulting Islam and the country's president, Mohamed Morsi.