MANILA—President Rodrigo Duterte accused the main shareholders of water concessionaires Manila Water and Maynilad of "syndicated estafa" over what he said were onerous provisions in their contracts with the government.

In a speech before quake victims in Digos City, Duterte renewed his attack on the two utility firms and their owners, saying their contracts violated Philippine anti-corruption laws.

"Yang nagtatanong kayo, 'Saan 'yung big fish? Saan 'yung mga corruption? Saan 'yung malalaki?' O i-deliver ko na sa inyo ngayon: si Ayala pati si Pangilinan," Duterte said.

(Those who are asking: Where's the big fish? Where are those involved in corruption? Where are the big ones? I'll deliver it to you now: it's Ayala and Pangilinan.)

Manila Water is part of the Ayala group of companies, while Maynilad is jointly owned by DMCI Holdings Inc and Metro Pacific Investments Corp., the latter headed by businessman Manny Pangilinan.

The President threatened to have the owners of the water concessionaires arrested.

"Kita mo, maski anong insulto ko hindi... hindi na sumasagot. Sigurado, swak sila. Syndicated estafa."

(You see despite how I insult them, they don't... don't answer back anymore. For sure, they fit. Syndicated estafa.)

The contracts of the 2 firms violate the country's anti-graft laws, Duterte said, and thus were "null and void" from the start.

He said some members of his cabinet were advising him to renegotiate the contract with Manila Water and Maynilad, but he dismissed this suggestion.

"Sabi ko, 'There is nothing to negotiate a contract that is null and void from the very beginning.' Because in that contract, the Philippines agreed to waive sovereignty. You cannot do it," he said.

The contracts of the two firms are set to end in 2022.

Justice Secretary Menardo Guevarra said 2 weeks ago that the government was not entertaining new players in the country's water distribution business, but was just renegotiating the terms of the concession agreements to remove 12 "onerous provisions."

Duterte has suggested giving the water contracts to Prime Water, a company owned by his political ally and the Philippines' richest man, Manny Villar.

Manila Water and Maynilad earlier dropped claims to P10.8 billion in compensation awarded to them by a Singapore-based arbitration court.

The award had prompted Duterte to accuse the two firms of economic sabotage.