Zardari, who along with his son was given the mantle of the party following the assassination of Benazir Bhutto, his wife and former premier, said the PPP would win a "vast majority" of the seats, the Press Trust of India reported.

Speaking to reporters after voting in Nawabshah in the southern Sindh province, Zardari said his party was set to secure a majority across the country, PTI reported.

The other main contending party is the faction of the Pakistan Muslim league led by Nawaz Sharif, another former premier ousted in 1999 in a bloodless military coup by President Pervez Musharraf.

Zardari was driven to the voting station in an armored car, ringed by dozens of private security personnel, the PTI report said.