The mob sexual harassment of a female student at Cairo University has caused outrage across Egyptian society.

The criticism was heightened when Gaber Nassar, the university dean, implied the woman had provoked the attack by wearing "inappropriate clothes."

Speaking to private satellite channel ONTV on Monday, Nassar said the woman had been wearing a long garment over her clothes when she entered the campus gates, but had later removed it, "which led to the incident occurring."

He later retracted his comments, saying he did not mean to justify the attack.

“I apologise for the misunderstanding,” he wrote on Twitter late on Monday. He had earlier said both the male harassers and the woman would be punished and possibly expelled for breaking university rules, but later denied the victim would be punished.

“The [victim] has not been referred for investigation and anyone who witnessed the incident should inform the university. We will not relent in the punishment of these harassers,” he wrote in another tweet. “The case will be referred to the prosecution,” he added.

The woman, wearing black trousers and a pink sweater, was surrounded by the group of male students who verbally and physically assaulted her, and tried to strip her, according to the anti-sexual harassment campaign I Witnessed Harassment.

The male students crowded around her while whistling and clapping until she managed to flee into the ladies bathroom, where they waited outside for her to come out.

Security guards escorted the victim out of the bathroom and off campus, while students continued to shout sexual insults and film her on their phones.

Media coverage made the situation worse. Television presenter Tamer Amin said it was not possible to show footage of the incident because it was "inappropriate."

“These are dancers' clothes… provoking, seducing, revealing much more than they should," Amin said about the victim.

His comments provoked outrage on social media, where people asked him to publicly apologise.

Sexual harassment has long been a serious problem in Egypt.

A study by the United Nations in April 2013, which interviewed hundreds of women in seven of Egypt's 27 governorates, revealed more than 99 percent of women had experienced some form of sexual harassment, ranging from minor incidents to rape.

Fathi Fareed, coordinator of I Witnessed Harassment, told Ahram Online that the group had met with Nassar, who showed an intention to cooperate with the movement to help raise awareness of sexual violence on campus and ways to combat it.

“The surrounding environment blames the victim,” Fareed said. “There's no deterrent, no media rhetoric to condemn this crime. There's not even a law criminalising it.”

Activists have been pushing for a law that specifically criminalises sexual harassment. Police reports are usually listed as honour crimes, attacking a woman or public obscenity.

Two draft laws have been presented, including one in 2012 by the National Council for Women, but none has been officially adopted.

“Sexual violence has moved from the street to transportation and universities, as everything spreads. This phenomenon has nothing to do with someone's educational status,” Fareed said.

In October 2012, his group was founded to document sexual assaults and raise awareness.

Nassar said the incident was the first ever at Cairo University, a claim refuted by Fareed, who said they had received dozens of complaints about sexual harassment on campus from both students and faculty members.

The National Council for Women issued a statement on Tuesday condemning the attack and Nassar’s comments.

“Does it make sense to put both the offender and the victim on the same level? How can we justify harassing her for wearing unfamiliar clothes?”

It stressed a draft sexual harassment law should be put up for discussion immediately and should not be delayed until a new parliament is formed.

“Mob sexual harassment incidents are happening on university campuses, 'academics' blame the victim. There's still a long way to go,” women's rights activist Mariam Kirollos wrote on Twitter.