"Without India we cannot have a final solution; that is certain. Their blessings must also be there," he was quoted as saying by the Indian Express newspaper Thursday.
Rajapakse, who will face Ranil Wickremesinghe in the presidential elections in November, said converting a 2002 truce into a lasting peace and pursuing economic development were his top priorities.
India has kept out of Sri Lanka's domestic affairs since it hastily withdrew its peacekeeping force in 1990 after both sides in the island nation - Sinhala and Tamil - turned against it. In 1991, a Sri Lankan Tamil rebel assassinated former Prime Minister Rajiv Gandhi.
Rajapakse said consensus was crucial to peace and a return to war was not an option.
"Without consensus ... you cannot settle this problem," he said, adding "We must realize that we have to satisfy the Singhalese people in the majority. Without them we cannot move forward."
Setting out his electoral agenda, Rajapakse, 59, said if elected he would seek direct talks with rebel leader Velupillai Prabhakaran.
"The first thing I will do is discuss this with Prabhakaran himself and have a practical approach," he said.