Judges in Pakistan face pressure to convict people accused of blasphemy, the UN's Special Rapporteur has said.

Gabriela Knaul said at the end of an 11-day visit to the country that lawyers were reluctant to defend people accused of blasphemy because of intimidation, the Associated Press reports.

Church leaders and human rights groups have long campaigned for the blasphemy laws to be repealed or significantly amended.

They warn that the laws are being misused by extremists to settle personal scores and even appropriate the property of minorities.

Christians, who make up less than two per cent of Pakistan's population, are frequently accused of blasphemy.

Under the blasphemy laws, insulting Islam, the Koran or the Prophet Muhammad is punishable by death.

Although no one has ever been executed for blasphemy in Pakistan, those accused face years in prison awaiting trial and even if found innocent and freed, are often forced to go into hiding because of the threat to their lives from extremists.

Knaul, who was in Pakistan to review its judicial system, said: "I am especially concerned regarding cases brought under the so-called blasphemy law as it was reported to me that judges have been coerced to decide against the accused even without supporting evidence.

"They are afraid of reprisals by local communities because of their interpretation of the law."

Lawyers who do decide to defend people accused of blasphemy often face intimidation and threats to their lives.

Minorities Minister and a committed Christian, Shahbaz Bhatti, was killed by gunmen over his support for reform of the blasphemy laws.

His death came just months after the Governor of Punjab, Salman Taseer, was shot dead by his own bodyguard after he expressed support for the acquittal of Asia Bibi, a Christian woman sentenced to death for blasphemy in 2010.