The kidnapped son of a Pakistani governor who was murdered after he criticised the country's blasphemy laws was freed on Tuesday, authorities have said.

Shahbaz Taseer, in his 30s, had been missing for more than four years, ever since he was abducted in Lahore months after his father, Punjab Governor Salman Taseer, was killed in 2011.

The Pakistani army said Shahbaz Taseer had been rescued by intelligence agents in the southwestern province of Baluchistan.

"Shahbaz was recovered safe and sound," Baluchistan police inspector general Ahsan Mehboob told Reuters. Intelligence agents and counter-terrorism officers found Taseer after receiving information he was being held in a hotel in Kuchlak, 25 km north of Quetta, the provincial capital, Mehboob said.

No arrests were made in the raid, and there was no confrontation with the captors, he added.

Last week, Salman Taseer's former bodyguard, Mumtaz Qadri, was hanged for the murder. The killer's funeral attracted tens of thousands of supporters who proclaimed him a hero for defending Islam.

On Monday, a suicide bomber killed at least 10 people near a court, an attack the Pakistani Taliban's Jamaat-ur-Ahrar faction said it had committed to avenge Qadri's execution.

Salman Taseer had spoken in support of Asia Bibi, a Christian woman sentenced to death for blasphemy and had called for the laws that mandate the death penalty for insulting Islam to be revised. After his death, Taseer's family received multiple threats from religious hard-liners.

On the day of Qadri's execution, another of Taseer's sons, Shehryar, tweeted: "MumtazQadri being hanged is a victory to #Pakistan. NOT the #Taseer family. The safe return of my brother is the only victory my family wants."

According to the director of the Centre for Legal Aid, Assistance and Settlement (CLAAS), which works on behalf of persecuted Christians in Pakistan, Christians in the county are living in fear following Qadri's hanging. Nasir Saeed said: "Christians are scared and cautious. The execution will also enhance the threat to the lives of those who are charged under blasphemy law and are currently detained in various prisons."

Quadri was unrepentant for his actions, telling his attorney: "even if Allah gave me 50 million lives, I would still sacrifice all of them". He is regularly referred to as a 'martyr' on pro-Islamist news outlets.

Another campaigner against the country's oppressive blasphemy laws, Shahbaz Bhatti, could be formally declared a martyr after local Roman Catholic authorities formally opened his cause.

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."

Additional reporting by Reuters.