The development came hours after President Duterte said he will not run for vice president in 2022 and will retire from politics when his term ends.
Philippine President Rodrigo's daughter will run for president in next year's election and her father's long-time aide, who filed his vice presidential candidacy, will be her running mate, broadcasting firm ABS-CBN news has reported.
Sara Duterte-Carpio is currently mayor of Davao, the Philippines' third-largest city, and filed on Saturday to run for mayor again. She has previously said she would not run for national office next year.
ABS-CBN news based it s report on an interview that Duterte had with a broadcast journalist right after he announced that he was retiring from politics while accompanying his closest loyalist, Senator Christopher "Bong" Go, who filed his vice presidential candidacy.
He was asked: "So is it clear, Sara-Go?"
"It is Sara-Go," Duterte said in response.
When asked to confirm what the president said, Duterte-Carpio's spokesperson, Mayor Christina Garcia Frasco told Reuters: "The extent of my knowledge is also what was reported in local news. We have no comment on the same."
Go did not immediately respond to a Reuters request for comment.
ABS-CBN news said it obtained permission from the broadcast journalist to use the video showing Duterte outside a hotel in Manila where the registration of candidates was taking place, and that a transcript was also provided.
In the same clip, Duterte was asked when his daughter would file her candidacy for president, he said: "I really do not know. I do not have any idea at all".
Asked if he had given his daughter permission to run for president, he said: "Ah, no, actually we don't talk about politics, ever since we never talk about politics. I would say that it is for the better," Duterte was quoted as saying.
One-term limit for the presidency
Duterte, 76, said on Saturday he was retiring from politics, a surprise move that fuelled speculation he was clearing the way for a presidential run by his daughter.
He had been expected to run for the No. 2 job, a plan most Filipinos oppose as violating the spirit of the constitution which sets a one-term limit for the president to stop power being abused.
Duterte-Carpio's mayorial re-election filing, did little to douse speculation she has her eye on the presidency.
Political analysts were sceptical, noting that last-minute changes were still possible, as in 2015 when Duterte entered the presidential election race at the eleventh hour and won by a huge margin, and Duterte-Carpio, they said, could do the same.
Candidates have until October 8 to register, but withdrawals and substitutions are allowed until November 15, leaving scope for last-minute changes of heart.