Rodrigo Duterte, the tough-talking mayor of Davao City, said China should respect the 200 nautical mile Exclusive Economic Zone granted to coastal states under international law and should team up with the Philippines to jointly exploit offshore oil and gas.
"I would say to China, 'do not claim anything here and I will not insist also that it is ours'. But then I will just keep (turn) a blind eye," he told reporters, as results of an unofficial vote count came in showing him winning a hefty 40 percent of the votes.
"If you want joint ventures, fine, we can get the gas and the oil," he said. "I believe in sharing."
Tensions between the Philippines and China have risen as an international tribunal in the Hague prepares to deliver a ruling in the next few months in a case lodged by Manila in 2013 that could undermine Beijing's claims to 90 percent of the South China Sea, also known as the East Sea to Vietnam. China has rejected the court's authority.
Duterte, 71, has puzzled diplomats with what has so far been a contradictory position on how he would deal with China's assertiveness and a blockade by its coastguard of waters and islands claimed by the Philippines.
During one presidential debate he said he would call for dialogue with Beijing, but moments later added he would ride a jet ski to disputed Spratly islands occupied by China and plant a Philippine flag there.
But on Monday he said that talks were needed between claimant countries - the Philippines, Vietnam, Malaysia, Brunei, Taiwan and China - plus big powers like the United States, Australia and Japan.
"They would want a multilateral roundtable discussion, probably this year," he said of Western countries.
"I do not think anyone is interested in going to war. Although we are allies with America, we will agree to, say, multilateral participation."
China's dominant presence in disputed waters has complicated protracted Philippine efforts to exploit oil and gas in coastal waters by local firms, which operate mostly with foreign partners.