MANILA - A member of the charter change consultative committee has included Sabah as part of the Philippine territory in his proposed constitutional amendments.

Former Senator Aquilino "Nene" Pimentel said the government should continue to push for the country's claim to Sabah in a way acceptable to international laws.

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"There should be a way that is acceptable under international laws to assert our claim to Sabah," he told ANC Tuesday. "I think we can defer it a little bit more but to say that we stop doing it is not in the context of my proposal."

Pimentel's proposal for the new federal government includes 12 federal states: Northern Luzon, Central Luzon, Southern Luzon, Bicol, Eastern Visayas, Central Visayas, Western Visayas, Minparom, Northern Mindanao, Southern Mindanao, Bangsamoro.

Metro Manila will be the "federal capital," said the former senator, likening it to the United States' Washington DC. He said the government later on can add Sabah as the 13th federal state.

"Eventually once we have asserted our sovereignty and rights over Sabah, we should include Sabah. Not only Sabah, but also Scarborough, Benham Rise, and Spratlys," he said.

President Rodrigo Duterte promised during the 2016 elections that his administration will pursue the Sabah claim "but only by peaceful means."

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The Philippines stakes its claim to Sabah by citing an 1878 land lease agreement between the Sultanate of Sulu and the British North Borneo Chartered Co.

The Philippines maintains that the agreement was only for leasing the land and did not render Sabah part of Malaysia when it was formed into a federation in 1963.