ISLAMABAD: Punjab government said on Tuesday it would bar Islamist organisations from staging rallies commemorating a killer whom many religious groups consider a hero for assassinating a prominent politician who had called for the reform of blasphemy laws.

Mumtaz Qadri was executed on February 29 last year for murdering Punjab governor Salman Taseer, whom he served as a bodyguard before killing him in the capital Islamabad in 2011.

Taseer had enraged religious hardliners by calling for the reform of blasphemy laws that mandate the death penalty for insulting Islam.

The blasphemy law and Taseer's murder have exposed the growing gap between hard-line religious conservatives and liberals in Pakistan.

Members of Tehreek-i-Labaik Ya Rasool Allah, a coalition of Islamist groups which planned to stage a rally on Wednesday to honour Qadri, said two of its leaders had been placed under house arrest ahead of the one-year anniversary of Qadri's death.

The coalition has in the past led vast street protests against Qadri's execution and this week it planned to stage a march from the eastern city of Lahore to a shrine built over Qadri's grave on the outskirts of Islamabad.

"All types of protests or rallies are strictly prohibited right now, especially in this kind of security environment," said Punjab government spokesman Malik Ahmad Khan, referring to a spate of Islamist attacks in Pakistan this month.

More than 130 people have been killed in recent weeks by militant groups after the Taliban and Islamic State carried out bomb attacks across the country.

More than 100 people are charged with blasphemy and jailed each year in predominantly Muslim Pakistan, many of them Christians and other minorities. Critics say the law is often invoked in cases of personal disputes.

"The government has put our leaders under house arrest but we are not scared," said Ali Raza, a Pakistani member of Tehreek-i-Labaik who works in China.

He said he had traveled to Qadri's shrine for the anniversary.

"If you are a Muslim, you will be happy to be chopped up into a thousand tiny pieces but you will not rest if someone disrespects the prophet. I will come here every single year."

People say a prayer over the grave of Mumtaz Qadri at the shrine built over his grave outside Islamabad, Pakistan February 27, 2017. (REUTERS)