Students discuss a controversial anti-abortion display at the University of Calgary in November. (Erin Collins/CBC)

Several students who took part in a graphic anti-abortion display at the University of Calgary have been charged with trespassing, a lawyer for the students says.

The students with University of Calgary Campus Pro-Life have to enter a plea by the end of the month and expect a trial later this year, Canadian Constitution Foundation's executive director John Carpay said in a release.

"The university is created by legislation, governed by legislation and receives more than 60 per cent of its funding from taxpayers," he said. "As a public institution, it does not have the right to discriminate against one group of students by censoring one viewpoint on an issue."

Leah Hallman, president of the anti-abortion group, said three students have been served legal papers, and she expects three more will also be served.

University lawyer Paul Beke said in November the Charter of Rights and Freedoms doesn't apply to universities, and freedom of expression protection doesn't extend to trespassers.

"Protesters are on the university's private property and they have refused to follow the university's instructions," Beke said at the time.

"Because they won't co-operate, they had to give notice to the protesters that they will become illegal protesters. So they will be dealt with legally if they do trespass."

Students set up display in November

The charges stem from November when several students set up posters on campus which showed fetuses and compared abortion to the Holocaust, the Ku Klux Klan and the genocide in Rwanda.

Earlier in the year, university administrators asked the group, which has about 30 members, to make the posters less visible, citing safety concerns.

When the students refused to comply, the school issued a letter threatening legal action.

The letter warned that the university would consider the students to be trespassing and that they would be subject to arrest, fines, suspension or expulsion.

The club set up the display anyway. University officials didn't kick the group off campus, but asked police to investigate.

The university also put up signs warning students and staff about the "extremely graphic" poster display.

Hallman said campus security took down their contact information in November and told them they could be charged with trespassing, but nothing happened until recently, after the group advised the school that they were planning to set up the display again this spring.

With files from Canadian Press