Railways minister Ghulam Ahmed Bilour also called on the Taliban and al-Qaeda to join the hunt and help accomplish the "noble deed."
Bilour spoke to reporters in the northwestern city of Peshawar a day after violent nationwide demonstrations against the "Innocence of Muslims" film left 21 people dead and more than 200 injured.
"I announce today that this blasphemer who has abused the holy prophet, if somebody will kill him, I will give that person a prize of $100,000," Bilour said, urging others to shower the killer with cash and gold.
"I also invite Taliban and al-Qaeda brothers to be partners in this noble deed," he added. "I also announce that if the government hands this person over to me, my heart says I will finish him with my own hands and then they can hang me."
Protests against the low-budget film have erupted across the Muslim world, leading to more than 50 deaths since the first demonstrations on September 11.
A French satirical magazine's publication this week of cartoons mocking the Prophet has further stoked anger.
The producer of the film, Nakoula Basseley Nakoula, is reportedly a Los Angeles-based 55-year-old Egyptian Copt and convicted fraudster, currently out on parole.
US media reports say Nakoula wrote and produced the film, using the pseudonym Sam Bacile before being identified. Police questioned him before he went into hiding with his family.
Thousands of Islamist activists in Pakistan staged demonstrations again Saturday but there was no repeat of the previous day's widespread violence.
More than 5,000 protesters, including hundreds of women, marched towards the parliament in Islamabad chanting "We love our Holy Prophet" and "Punishment for those who humiliated our Prophet".
Some 1,500 people from the hardline Islamist Jamaat-ud-Dawa and Sunni religious groups rallied in front of the US consulate in the eastern city of Lahore, chanting "The US deserves only one remedy -- jihad, jihad".
Smaller protests took place in the southwestern city of Quetta, as well as in Peshawar, where six people died in Friday's protests, and in the southern port city of Karachi, where 15 people were killed Friday.
Witnesses estimated that more than 45,000 people joined Friday's nationwide rallies, mainly members of right-wing religious parties and supporters of banned terror groups.
Demonstrators attack a cinema during a protest against an anti-Islam film in Karachi. AFP photo
Those numbers, however, were still considered small in a country of 180 million.
Four more people died overnight from wounds they received during the protests, taking toll of those killed across Pakistan on Friday to 21, health officials said.
The combined total of wounded in Karachi, Peshawar and the capital Islamabad was 229.
In Nigeria, meanwhile, tens of thousands of people protested in the second city of Kano, burning images of US President Barack Obama and stomping on the American flag.
The procession of men, veiled women and children stretched for several kilometres (miles) through the city, the largest in Nigeria's mainly Muslim north.
They shouted "death to America, death to Israel and death to the enemies of Islam". There were no reports of violence.
The demonstration was organised by the Islamic Movement of Nigeria, a pro-Iranian group that adheres to the Shiite branch of Islam.
In Lebanon, thousands of supporters of the Shiite Hezbollah movement took to the streets in the southern town of Bint Jbeil.
Women in black chadors carried colourful Islamist flags alongside young children holding the Koran, the Muslim holy book.
Hezbollah parliamentary representative Nawaf al-Moussawi told the crowd the film was "... not merely a trivial creation carried out by a group, but American politics intended to be disseminated to the Western world."
He also warned against reprisal attacks on the Christian community.
In east Jerusalem about 500 Palestinians, accompanied by a marching band, protested against both the film and the cartoons in the French satirical weekly Charlie Hebdo.
In Germany, 1,500 people staged a peaceful protest in the western city of Dortmund, a day after similar demonstrations in other German cities.
A German far-right group's threat to screen the video has prompted heated debate over whether or not the authorities should ban the film on security grounds.
In neighboring Austria, about 500 people protested outside the US embassy in the capital Vienna.
In France, riot police were out in force in several parts of Paris to enforce a ban on protests, a week after an unauthorised demonstration against the film led to 150 arrests.
Social networks had been awash with appeals for French Muslims to defy the ban and hold fresh protests.
French police have arrested a man in the western city of La Rochelle for having allegedly called on a jihadi website for Stephane Charbonnier, chief of satirical weekly Charlie Hebdo, to be decapitated.