The European court today ruled in a test case that the Irish Republic's refusal to allow abortion breached the human rights of one woman with a medical condition, but not two others.

Campaigners were disappointed that all three cases were not upheld, but hoped the partial judgment against the Republic would result in clarification of women's abortion rights. It is now likely that a new Irish government elected to office this coming March will have to deal with demands for a referendum on the issue.

Abortion is banned in the Republic and legalisation requires a referendum to change the constitution. After a 1983 referendum, the unborn child is an Irish citizen with full rights. About 5,500 women travel to England and Wales every year from the Republic to seek an abortion, at considerable cost and distress, according to critics of the policy.

Three women, known as A, B and C, took their cases to the European court of human rights. The first was a recovering alcoholic whose four children had been placed in foster care. She sought an abortion because she believed that having another baby would jeopardise her chances of getting her children back. The court accepted that she was living in poverty – she borrowed from a money-lender to cover the cost of travelling to a private clinic in London. The second woman was unmarried and not prepared to become a single parent.

In both these cases, the Strasbourg court ruled Ireland had not breached the women's human rights. But it took a different view of the third case. This woman had undergone treatment for a rare cancer. While in remission, she had medical checks that could have had an effect on the development of the foetus and believed there was a chance the pregnancy could trigger a recurrence of her cancer.

"The court considered that the establishment of any such risk to her life clearly concerned fundamental values and essential aspects of her right to respect for her private life," said the judgment. If the woman's doctor found her health was at risk and advised an abortion, both ran a serious risk of criminal conviction and imprisonment if his view was later found to be against the Irish constitution, it said.

Abortion Support Network, a voluntary organisation which helps women travel from Ireland to the UK, said it was extremely disappointed that the court had not upheld all three challenges.

"While we are encouraged by the ruling that woman C, who was undergoing chemotherapy when she fell pregnant, had her human rights violated, we are deeply saddened that the court chose not to recognise the hardships faced by the two other claimants in the case," said its director, Mara Clarke.

"The sooner the Irish government rectifies this long-standing injustice, the sooner women will be able to make their own decisions about abortion and make choices that are right for them."

Marie Stopes International, which provides sexual and reproductive healthcare services, said the judgment was an important first move towards providing women in Ireland with clarity over their rights.

"This is a landmark ruling and an important first step to ensuring that women have access to safe abortion services in Ireland," said Tracey McNeill, director of Marie Stopes in UK and western Europe. "The court highlighted that the law needs to be changed to ensure that doctors feel confident that they won't face prosecution for providing abortions if the woman's life is considered to be at risk. What we would like to see in the future is Irish women having the same fundamental rights to choose as people in the rest of Europe.

"We commend the bravery of the three women that have taken this long battle to the European court. Each faced a distressing ordeal in order to access an abortion and they highlight that even in some of the most difficult circumstances, women are denied access to abortions in Ireland."

As the rulings of the European court are binding, the Irish government will be under pressure to implement a woman's right to an abortion if her life is at risk. It is understood that the judgment is being considered by the Republic's department of health and the Irish attorney general.

Given that an alternative Irish government is likely to be comprised of Fine Gael and Labour, the prospect of a referendum on abortion could prove divisive. Fine Gael opposes introducing abortion into Ireland but there are many in the Irish Labour party who support a woman's right to choose.