Activists in Cyprus have described the determination of a British teenager to overturn a conviction that she lied about being gang-raped on the island as “a critical moment” for women’s rights.

Ten days after the 19-year-old received a suspended four-month sentence for the offence of fomenting public mischief, her lawyers filed an appeal against the conviction before the country’s supreme court.

“This is a very critical moment for Cyprus regarding the rights of women in our courts,” said Argentoula Ioannou, the activist lawyer who appalled by the way the case had been handled set up the Network Against Violence Against Women on the island.

“For the first time the highest court in the land will have to decide whether a woman was given a fair trial, whether her rights were violated and whether our republic met its obligations as an EU member state.”

The appeal, submitted Thursday, is the latest attempt to clear the student’s name. Lawyers acting on behalf of the Briton, who flew back to the UK last week after five months of court proceedings in Cyprus, say they will resort to both the European court of justice and the European court of human rights if the appeal fails.

The guilty verdict had hinged on a written confession in which the teenager had withdrawn the complaint but which her defence team argues was extracted under duress in the absence of a lawyer or translator after eight hours of police questioning.

“When the trial proceedings are considered dispassionately, it is clear that the teenager did not receive a fair trial,” said Michael Polak of the legal aid group Justice Abroad which is coordinating the appeal. “The treatment of her representatives and witness was in complete contrast to the treatment the prosecution and its witness experienced.”

The woman’s conviction not only breached her rights under Cypriot law, but amounted to a breach of the country’s “international obligations under the European convention on human rights and as a member of the European Union,” he insisted.

The Briton, who has not been named for legal reasons, says she was gang-raped by up to 12 Israelis in a hotel room in Ayia Napa last July while on a working holiday in the party resort. The youths, who were aged between 15 and 22 at the time, returned home after police announced she had retracted the rape claim. The student, meanwhile, spent almost five weeks incarcerated in Nicosia general prison and was forced to relinquish her passport and remain on Cyprus.

Sitting in Famagusta district court in the coastal town of Paralimni, Judge Michalis Papathanasiou, who had earlier found her guilty of public mischief and manufacturing “an imaginary offence”, allowed the teenager to walk free as Cypriot and Israeli activists protested noisily outside the court. Her sentence was suspended for three years.

It is hoped, under an expedited appeals process, the case will be heard within six months. The teenager has been described by expert witnesses as suffering from severe post traumatic stress disorder and the defence is keen for the conviction not to impede her return to normal life.

The case is also being closely watched by women’s groups in Israel who have also rushed to the Briton’s defence. Leia Lazar, who was among the activists who flew into Cyprus in support of the teenager, told the Guardian: “We believe this woman because no one would go to the police in a foreign country and report gang-rape if it wasn’t true. Violence against women in Israel is a big problem. Official data shows that one in five women are raped and very often they are filmed having consensual or non-consensual sex and then find that those encounters end up on the web.”

Cypriot authorities claimed the teenager had lodged her initial complaint after angrily discovering some of the youths had secretly videoed what had originally been an act of consensual sex with one of the group. “Several of the boys had very strong political connections which is why no one wants to talk about this in my country and the Israeli media have covered it so unfairly,” Lazar said.