Shahbaz Bhatti, the Pakistan minister for minorities murdered for his opposition to the country's oppressive blasphemy law, should be declared a martyr by the Church, Catholics there say.

In Catholic practice the process for declaring martyrdom can begin five years after a person's death. Bhatti was murdered on 2 March 2011 and local authorities have begun to collect evidence to support their claim.

Shamaun Alfred Gill, spokesperson for the All Pakistan Minority Alliance, the political party formed and led by Bhatti, told International Christian Concern: "A committee from the Vatican is reviewing Shahbaz Bhatti's struggle for equal rights and gathering information on his murder. We are hoping that this outspoken hero of the nation will soon be given the official status of martyr by the Vatican for raising his voice for the voiceless in this country."

Speaking at a ceremony marking the fifth anniversary of the murder, the Archbishop of Karachi, Joseph Coutts, said: "He spoke with faith and demonstrated courage. Thanks to him the voice of Pakistan's Christians was heard. He paved the way for us. He was a good Catholic and gave his life for his mission."

He told Fides: "As Pakistani Christians we face numerous challenges every day. Many will have heard of the so-called blasphemy law and the emblematic case of Asia Bibi, an innocent Christian mother sentenced to death. Our daily mission is to bear witness to peace and to love where there is so much violence in this country torn apart by terrorism. As Christians our mission is love and love of Christ helps us not to lose hope."

Bhatti was shot by three masked men as he left his mother's home in Islamabad.

He had recorded a video to be released in the event of his death, in which he said: "I want to share that I believe in Jesus Christ, who has given his own life for us. I know what is the meaning of 'cross,' and I follow him to the cross."

He said: "I am a man who has burnt his bridges. I cannot and will not go back on this commitment. I will fight fanaticism and fight in defence of Christians to the death."

Bhatti's death came only months after the murder of Salman Taseer, governor of the Punjab, who was also an opponent of the blasphemy laws. Taseer's murderer Mumtaz Qadri was hanged on Monday, with thousands demonstrating at his funeral and declaring him a martyr for Islam. Bhatti's killer has never been caught, though the Tehrik-i-Taliban group claimed responsibility.