Colombo, Aug 17 (IANS): Former Sri Lankan President Mahinda Rajapakse on Monday cast his vote in the parliamentary polls aiming to become the country's new prime minister if his opposition party wins in the election.

Rajapakse, who was defeated by his close aide and former health minister Maithripala Sirisena in a presidential election in January, is looking at becoming the country's new prime minister if his opposition United People's Freedom Alliance (UPFA) wins majority in Monday's polls, Xinhua news agency reported.

"I am confident in victory," he told reporters after casting his vote in his southern hometown of Hambantota along with his wife and sons. UPFA is aiming at 113 seats at least to win a majority to form the next government in the 225-member Sri Lankan parliament.

Rajapakse's re-entry into the political arena has been strongly opposed by President Sirisena, who is also the party chairman, and a group of party members who defected to ally with Prime Minister Ranil Wickremesinghe's United National Front (UNF) to contest the polls.

In the month-long election campaigning which ended on Friday, the former leader vowed to provide relief to the poor and increase the salaries of the public sector employees.

He also pledged to focus more on education and provide broadband facilities to all families so that the younger generation could enter the online market.

He also promised to introduce a new constitution of the country within six months.