Railways Minister Ghulam Ahmad Bilour told reporters that he would pay the reward for the “sacred duty” out of his own pocket.
He suggested the Taliban and al-Qaeda would be eligible for the reward.
His comments came a day after at least 20 people died in clashes between anti-film protesters and police.
“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,” the minister said.
Friday’s violence occurred in cities throughout the country, with Karachi and Peshawar among the worst hit.
The film, denigrating Islam’s Prophet Muhammad, has sparked violent protests throughout the Muslim world in recent weeks.
Scores of people were reported to have been injured on Saturday in a clash in Bangladesh’s capital Dhaka between police and hundreds of demonstrators.
Police fired tear gas and used batons to disperse stone-throwing protesters who set several vehicles alight, the Associated Press news agency reports.
In Pakistan itself, a peaceful demonstration was held in Islamabad. Protesters marched through the capital and gathered near parliament, chanting slogans against the filmmaker and demanding punishment.
And in Nigeria, tens of thousands of Muslims marched in the northern city of Kano in a protest that passed of peacefully.
Marchers shouted “death to America, death to Israel and death to the enemies of Islam” in a procession several kilometres long. US and Israeli flags were dragged through the dirt.
The exact origins of Innocence of Muslims, the low-budget film that has prompted the unrest, are unclear.
The alleged producer of the trailer of the film, Nakoula Basseley Nakoula, is in hiding.
Anti-US sentiment grew after a trailer for the film dubbed into Arabic was released on YouTube earlier this month.
US citizens have been urged not to travel to Pakistan and the US embassy has paid for adverts on Pakistani TV showing President Barack Obama and Secretary of State Hillary Clinton condemning the film.
Although US targets have borne the brunt of protests against the film, anti-Western sentiment has been stoked further by caricatures of the Prophet Muhammad published this week in the satirical French magazine, Charlie Hebdo.
France shut embassies and other missions in about 20 countries across the Muslim world on Friday.