KUALA LUMPUR, Oct. 4 -- Former law minister Datuk Zaid Ibrahim says Sarawak premier Abang Johari Openg's assurance that Petros will not undermine Petronas rings hollow while the state oil company seeks a bigger role in the gas business and Sarawak continues to question the federal legal framework governing petroleum.

Writing on Facebook, Zaid said the central issue was Petros's desire to take over the gas aggregator role currently performed by Petronas in Sarawak.

That role is integral to the gas value chain, he said, and cannot be transferred without affecting Petronas's commercial position. He estimated Petronas's Sarawak gas business at about RM10 billion annually.

Zaid said the impact was already visible in the confusion created by...