Mian Nisqar Gul, the Minister for Prisons in NWFP, was hit by three bullets when the gunmen opened fire at his car in Darra Adam Khel area, senior provincial minister basher Ahmed Bilour said.
No group claimed responsibility for the attack but Bilour blamed militants for the ambush.
Meanwhile in Dera Ismail Khan, at least 20 people were injured when an unidentified attacker lobbed a grenade in a market on Thursday.
The attacker, who was on a motorcycle, entered Topawala Bazar and threw a grenade at people standing near a shop at around noon. A seven-year-old girl was among the injured.
Pakistan unleashed helicopter gunships and artillery to kill scores of Taliban fighters, officials said on Thursday, after opening a second front against militants near their stronghold in the Waziristan tribal region.
A military statement said on Thursday that during the last 24 hours 66 militants had been killed in fighting mostly in Bannu and South Waziristan, but also Swat.