Police commando Malik Mumtaz Hussain Qadri, who was led away smiling on Tuesday after gunning down his boss outside an Islamabad coffee shop, has said he killed because the governor wanted to reform controversial blasphemy laws.

"He has recorded his confessional statement for the murder... in which he said that he killed Salman Taseer on his own and there was no involvement of any Islamic or militant organisation," senior police official Haroon Joya told AFP.

Members of the main ruling Pakistan People's Party (PPP), to which Punjab provincial governor Taseer belonged, suggested that his killing was part of a wider plot, and slammed security failures that led to his death.