Minister Nimal Siripala de Silva said it would not have been possible for the SLPP to win the Presidential election, without the support of the SLFP.
"Had the SLFP decided to support another candidate, SLPP candidate Gotabhaya Rajapaksa would have lost close to 800,000 votes.
De Silva's remarks come in the wake of statements by several SLPP members that their party was not "indebted" to any other party for the election victory.
The Minister said the SLFP was one of the principal factors behind Gotabhaya Rajapaksa's victory.