According to the BBC, Grand Lotto participants have to select six numbers from one to 55. They win when all six chosen numbers match those drawn by the lottery’s operator.
Philippines senate minority leader Koko Pimentel wrote in a Facebook post that the “strange and unusual” result from Saturday’s Grand Lotto warranted an investigation.
“I will file a resolution, because this is my concern, these lotto games are authorised by the Republic of the Philippines,” he said. “Therefore, we need to maintain and protect the integrity of these gambling games that we have authorised.”
Mr Pinmentel also said he would seek the opinion of statisticians and mathematicians regarding results of PCSO draws.
Senator Risa Hontiveros said in a statement that she supported an investigation to rule out any perceptions that the jackpot results had been “manipulated”.
“We also want to make sure the system is secure, free from glitches and trustworthy,” she said.
The PCSO, which is government-owned, pointed out in a local news conference that Filipinos tend to bet on “number sequences”.
Its general manager Melquiades Robles said in a Facebook post on Sunday that lottery “is a game of chance, nothing is definite and it is uncontrollable”.
“To the 433 new jackpot winners, it pays to be loyal!” he added.