Nicholas Ty, undersecretary for the Philippines Department of Justice, told ITV News that the government's Anti-Trafficking and Online Sexual Abuse and Exploitation of Children taskforce in Cebu is investigating the matter.
The allegations were first published by The Sun, which reported that Meghan's half-brother, Thomas Markle Jr, 60, said he found "hundreds" of child sex images on computers and a cellphone left behind at his father's home when he moved from the Philippines earlier this year.
Mr Markle Jr told The Sun he submitted a police statement in the Philippines and also reported his discovery to the FBI Hotline, the state police in Pennsylvania and the US-based National Centre for Exploited and Missing Children in July. "When I found this material I was horrified and I had no option but to report my dad," he said. "I won't speak to my father ever again unless I'm called to give evidence against him."
Thomas Markle Sr, 82, a former television lighting director, has vigorously denied the accusations. In an interview with the Daily Mail, he called them "sick lies" from a son with whom he has a troubled relationship. "I'm shocked, I'm hurt and I'm very upset that my son is making these accusations against me," he said. "I could never do what I'm being accused of. It's the worst thing anyone could accuse me of." He claimed to have had no access to the computers and phones in question in the two years since he left Mexico for the Philippines, according to the Daily Mail.
The Duchess of Sussex issued a statement on Friday saying she was "deeply distressed" by the allegations. She said a letter sent to the Metropolitan Police and Royalty and Specialist Protection in 2018 was shared with her and contained "troubling and disturbing allegations" against her father. She said she was given assurances the allegations were being investigated.
"I hope it can now be understood that, despite certain media publications' distortion over the years, any distance from my father and my choice to not allow him to have contact with our children, was for one reason: to protect them," she said.
The Metropolitan Police said it is making internal inquiries regarding officers from the Royalty and Specialist Protection Command being involved in passing on the letter. A spokesperson said: "We are aware of media reports that officers from the Met's Royalty and Specialist Protection Command were involved in the passing on of a letter in 2018. We are undertaking inquiries internally in an effort to confirm this." It is understood the Met is not currently and has not previously investigated Mr Markle Sr.
The FBI released a statement on Friday evening. An FBI spokesman said: "The FBI is aware of the allegations and will provide support, as appropriate, to the Philippine authorities. We will also investigate any related allegations of federal violations of US law."
Thomas Markle Sr's eldest daughter, Samantha Markle, defended her father and accused Thomas Jr of "making up lies" to make money, the Daily Mail reported.
Mr Markle Sr did not attend Meghan's wedding in May 2018 after pulling out due to health issues, and has been estranged from the duchess since. He has suffered a series of strokes and recently had a leg amputated due to complications with a blood clot. He is now understood to be in a rehabilitation centre in Florida undergoing physiotherapy.