Nawaz Sharif, seen as the front-runner in Pakistan's election race, said he would not allow militant groups to attack India and would work to improve ties with New Delhi if elected.
"If I become the prime minister I will make sure that the Pakistani soil is not used for any such designs against India," Mr Sharif told CNN-IBN in an interview.
Despite recent strains, India and Pakistan's relations have improved after nosediving in 2008 when gunmen killed 166 people in Mumbai in a three-day rampage that India blamed on a Pakistani militant group.
According to opinion polls, Mr Sharif's Pakistan Muslim League (PML-N) is expected to win Saturday's general election after capitalising on the failure of the outgoing Pakistan People's Party (PPP) to tackle everything from power cuts to a Taliban insurgency.
The liberal, secular-leaning PPP has a long history of challenging the military's influence in politics while the military sees the party as corrupt and ineffective.
The poll comes after a civilian government has for the first time completed a full-five-year term. But whoever wins will inherit enormous problems.
One of them will be managing a difficult relationship with India.
The nuclear-armed neighbours have fought three wars since the partition of British-ruled India in 1947. India has for years accused Pakistan of supporting Muslim militants and sending them in to the Indian part of the divided Kashmir region to fight Indian forces.
Pakistan denies arming the militants saying it only offers moral support to the people of Muslim-majority Kashmir.
Although the two countries began a peace process in 2004, they remain deeply suspicious of each other.
Their antagonism has spilt over into Afghanistan where they compete for influence and where they have tended to support rival Afghan forces.