Campaigners in Pakistan say the case of Asia Bibi – the first woman to be sentenced to death for blasphemy – highlights the need for urgent reform of laws that are routinely used to persecute minorities and settle grudges.

The 45-year-old Christian, who has at least two children, was sentenced to death by a court in Sheikhupura, near Lahore, after prosecutors accused her of insulting the Prophet Mohamed and promoting her own faith. Her family have rejected the allegations and launched an appeal. "We have never ever insulted the Prophet or Islamic scripture, and we will contest the charges," said her husband Ashiq Masih.

While Mrs Bibi may be the first woman to be sentenced to death, Pakistan's blasphemy laws – particularly section 295C of the penal code, introduced by the late dictator Zia ul-Haq – are commonly used against both non-Muslims and Muslim minorities.

Earlier this year, police reinforcements had to be called to Faisalabad when two Christians charged with blasphemy were shot dead outside the court. In 1998, John Joseph, the then Catholic Bishop of Faisalabad, committed suicide to protest against the treatment of Christians.

The campaign to confront the country's blasphemy laws has existed for some years but activists say the movement is hampered by the danger of being accused of undermining Islam. Because of fear of religious conservatives, some of those who would like to see the laws scrapped feel compelled to call for reform rather than repeal.

Human Rights Watch is among the groups that have called for sections 295 and 298 to be scrapped. "Asia Bibi's case should serve as a wake-up call to Pakistan's independent judiciary which urgently needs to address bigotry and incompetence in its ranks and to the government that needs to find the political will to repeal," said the group's Pakistan spokesman, Ali Dayan Hasan.

"The laws are discriminatory and intended as such and are used for precisely that purpose. So, the issue is not of their misuse but of the laws being on the statute books at all. Vague all-encompassing wording allows the laws to be used as an instrument of political and social coercion, legal discrimination and persecution."

Veteran human rights campaigner Asma Jahangir, who was recently elected head of the country's powerful Supreme Court Bar Association, is among those who have defended people accused of blasphemy, most famously in the case of a 14-year-old boy, Salamat Masih, who was accused of writing blasphemous words on the wall of a mosque. After Ms Jahangir successfully defended the teenager on appeal, the judge who acquitted him was murdered.

"At first these laws were used against minorities but now a number of Muslims have also been victimised. Once someone is accused of blasphemy you have to be very strong to defend yourself," she said. "Every time something like this [case] happens, there is a loud noise about reform. There is a draft reformed law that is with the government but the government is sitting on it. It's such a tricky issue because of the noise made by the extreme right."

The precise details of Mrs Bibi's case are unclear. Reports say the woman, who lives with her family in the village of Ittanwali, west of Lahore, had been working in the fields in June last year when she was sent to fetch water. When she returned, some Muslim women refused to drink it, saying it was unclean because it had been carried by a Christian. The women then fought.

At that point the other women went to a local cleric, Qari Salim, and several days later he filed a legal complaint with the police. When the case was eventually concluded last week, in addition to being sentenced to death, Mrs Bibi was also ordered to pay a fine of 300,000 Pakistani rupees (£2,180).

Last night, Mrs Bibi's husband told The Independent: "My wife was picking phalsa in the fields when she had a fight with her other workers over some triviality. The other three got together and accused my wife of desecrating the Holy Koran It was not even a men's fight in the village, but a trivial tussle between women."

Campaigners say many of the blasphemy cases that come to court are the result of personal grudges or disputes that have ended with one side or the other resorting to the powerful legislation to settle the issue.

While no one has yet been executed for blasphemy, the laws carry severe punishments. Earlier this year Pakistan's Supreme Court released a woman who had been held in jail for 14 years for blasphemy.