A letter making a "number of claims" relating to the Duchess of Sussex's father was received by the Metropolitan Police in 2019, Scotland Yard has confirmed.
The Met said it passed the information relating to allegations outside the UK to the office of the Duke and Duchess but did not share it with other law enforcement agencies.
It was reported on Friday that images of child sexual abuse allegedly belonging to Thomas Markle, 82, had been found in his former home in the Philippines. Markle, who is based in the US, denies possessing any such images.
Meghan said she was informed about "disturbing allegations" about her estranged father in 2018. The Met said it was reviewing the matter and deciding whether to refer itself to the police watchdog.
Responding to Saturday's developments dating the letter to 2019, a spokesman for the duchess said "any discrepancy of a few months" was "an understandable consequence of that passage of time".
The claims were first carried by the Sun newspaper, which later said that the letter made direct allegations of child sex abuse against Markle.
In a statement, Scotland Yard said: "Following a thorough review of Met Police systems and records, we have confirmed that in January 2019, we received a letter containing a number of claims about alleged offending outside the United Kingdom.
"It was sent to the MPS Protection Command to raise concerns in relation to the security of the Duchess of Sussex.
"The letter was reviewed and a decision was made that it should be passed to the office of the Duke and Duchess of Sussex for their awareness. The details of the allegations in the letter were not shared with other law enforcement agencies.
"The MPS is reviewing the handling of this matter in 2019 and considering whether a referral to the IOPC is necessary to review our approach."
Markle moved to the Philippines last year after he had a series of strokes.
He is reportedly now living in a Florida rehabilitation centre learning to walk again after having a leg amputated in 2025.
Meghan's half-brother Thomas Markle Jnr claimed he found a stash of images belonging to his father at his former Philippines home, the Sun reported.
He is said to have told police he discovered child abuse videos and pictures among the items. He is understood to have contacted the FBI in July.
In a statement released by Meghan on Friday she said that when she received the information of the claims against her father she was "given assurance that these were being investigated".
Meghan said she hoped it could be understood why she had kept her distance from her father and did "not allow him to have contact with our children".
Authorities in the Philippines have confirmed they are investigating the allegations about Meghan's father.
The BBC was told on Friday the matter was being investigated by an anti-human trafficking and child sexual exploitation task force.
Philippines Interior Minister Jonvic Remulla separately said national police had secured his computer and would carry out a digital forensic examination.
Meghan is the only daughter of Markle and her mother Doria Ragland.
He pulled out of attending Meghan and Harry's wedding in 2018 - citing ill health - and they became estranged.
The duke and duchess moved to the US in 2020 after stepping down as working royals.
They returned to the UK with their children this year after six years away.