"We will not give up anything there. Those are our entitlements. Every country in the world is given their own fish pond. You cannot give that up, you can only negotiate to prevent war," The President said.
"Not even the President of this country can give up the claim. You are not allowed to do that. That is one sure way to impeachment," he added.
Duterte, who is set to visit China on October 18 to 21, said Manila cannot "go into a rage and fight" Beijing, leaving it with no other option but to pursue diplomatic negotiations.
"What do you think will happen to my country if I choose to go to war? I fight alone? Or I'll call upon other countries to help me. Who would die for my country except us? We could only talk. That's why they invited me for talks, so I will go," he said.
"What do you think will happen to my country if I choose to go to war? I fight alone? Or I'll call upon other countries to help me. Who would die for my country except us? We could only talk. That's why they invited me for talks, so I will go," he said.
The President also maintained that he cannot use the arbitration court's verdict to pressure China.
"It will be arrogant of me to go there and say, 'I'm going there to fight for this and that,'" he said.
"You have to go there with a little bit of courtesy. But when we are already in front of each other, then we say, this is it, we do not go."
Foreign Affairs spokesman Charles Jose last Friday said Duterte may discuss the South China Sea row with his counterpart, Xi Jinping. The two leaders are expected to sign several agreements to boost ties between the Philippines and China.
The President is also expected to meet with the Filipino community in China, and deliver the keynote address at the Trade and Investment Forum, which will be attended by Filipino and Chinese investors.
Duterte's state visit to China will be the first meeting between the heads of states of the two countries in five years, after ties were affected when the Aquino administration decided to file a case against China before an arbitral tribunal.
Before leaving for Beijing, Duterte is first scheduled to fly to Brunei on Sunday for a state visit where he will hold bilateral talks with Haji Hassanal Bolkiah, Sultan and Yang Di-Pertuan of Brunei Darussalam.
In a speech on Sunday, President Duterte reiterated that there will be no bargaining of Philippine territories with China.
"We do not bargain anything there. We continue to insist that it is ours," Duterte said. "I will be very careful not to bargain for after all, I could not give what is not mine."