Women dressed in stark black, their faces veiled and their hands sometimes gloved, are becoming a common sight in Cairo, a trend that worries the government as it battles a lurch towards fundamentalism.

Most Muslim women in Egypt wear the hijab, which covers the hair, but the niqab, which covers the entire face, is becoming more popular on the streets of Cairo.

The issue has been brought into sharp focus following reports that Mohammed Tantawi, head of the Islamic Al-Azhar University, told a girl to remove her niqab when he toured a high school funded by his institution.

Mr Tantawi, the country's top religious authority, reportedly also said that he intends to ban the niqab at the university.

The ministry of religious endowments has distributed booklets explaining that wearing a niqab is un-Islamic while the Health Ministry wants to ban doctors and nurses from wearing the austere veil.

A decision has also reportedly been taken to ban students from wearing the niqab in the residences of the state-run Cairo University, although the university authorities deny this is the case.

Outside one the university's female residences, students said they had been stopped at the gates when they tried to enter wearing face veils.

"I don't understand their point of view. If it's for security, we can lift the niqab for security and show them our IDs," a student, who gave her name only as Heba, said.

Three veiled students huddled together nearby reviewing a complaint to the university that they had written and planned to lodge.

A security guard said he had been ordered to bar women from entering the residence wearing a niqab, even if they showed their faces for identification.

"From a security standpoint, the niqabs weren't a problem for us," he said. "They would show their faces when asked. I was surprised by the decision.

The Education Ministry denied there was a ban. "There is absolutely no ban against students wearing the niqab," said ministry spokesman Adli Reda.

Hossam Bahgat, of the rights watchdog the Egyptian Initiative for Personal Rights, said however he had received complaints from students who had been banned from entering Cairo University residences because they were wearing the niqab.

Mr Bahgat said there was a tendency to ban students with known opposition leanings from living in residences, especially those affiliated with the banned Muslim Brotherhood, the country's largest opposition group.

The niqab, however, is not usually associated with the Muslim Brotherhood, which advocates a peaceful transition to an Islamic government through elections.

Supporters of the niqab say wearing it brings women closer to God, and that they should be allowed to choose their own dress.

The majority of mainstream Muslim scholars - who agree a woman must cover her hair - say the niqab is unnecessary.