Imran Khan was targeted by a assassin in the city of Gujranwala as the former Pakistan cricketer took part in a reform rally.
The politician was in a car which was swamped by people when a gun was fired at the vehicle.
Khan - who used to be married to British heiress Jemima Goldsmith - was not injured during the incident, according to reports.
It understood more than one shot was fired at Khan, whose vehicle was surrounded by political opponents when it happened.
The former fast bowler was in the city as part of efforts by his party to unseat Pakistan's Prime Minister Nawaz Sharif.
Khan and his allies want to bring parts of the country to a standstill by occupying busy streets and refusing to budge until Sharif resigns.
Shairf is Pakistan's first PM to have gained power by democratic transfer and is curently locked in a battle of wills with opponents such as Khan, who want him out.
Khan leads the Pakistan Tehreek-e-Insaf party, the third largest in the country.