MANILA: Philippine Vice President Leni Robredo will decide this week if she will run for president, her spokesman said Sunday, after her arch-rival and incumbent Rodrigo Duterte declared he was retiring from politics.

Robredo, a vocal critic of Duterte's controversial drug war, would likely be the only opposition candidate in a crowded field in the May 2022 elections.

Her spokesperson Barry Gutierrez told AFP she has not yet accepted the opposition coalition's nomination, and will announce her decision before the filing deadline on October 8.

Duterte, who is constitutionally barred from seeking a second term, had declared in August he would run for the vice presidency.

But in a surprise announcement Saturday, he said he would retire -- which was met with deep scepticism among analysts.

Duterte made a similar announcement in September 2015, saying he "will retire from public life for good" only to declare his presidential bid two months later.

Duterte has not named a successor, but indicated his daughter Sara will run alongside his longtime aide Senator Christopher Go.

A broadcaster asked him Saturday if it was "clear it will be Sara-Go". Duterte responded: "It's Sara-Go."

Philippines' Duterte says will retire from politics

Surveys have shown Sara Duterte, the son and namesake of former dictator Ferdinand Marcos, boxing great Manny Pacquiao and celebrity mayor Francisco Domagoso are the frontrunners among potential presidential candidates.

Pacquiao and Domagoso have announced they are running, while the other two have yet to confirm.

Sara Duterte has not responded to AFP's request for confirmation.

Most of the top candidates have supported Duterte's controversial drug war, and political analysts say VP Robredo could struggle to compete if she decides to run.

Filipino voters are willing to elect a female president but they want her to be "feisty", said University of the Philipines political science professor Jean Franco.

"(VP Robredo is) too good, she's too nice."

Robredo, 56, narrowly won the nation's second top job in 2016, defeating Marcos' son and namesake.

Her victory dealt a blow to the political aspirations of the former dictator's family, including a possible return to the presidential office.

The Philippines' election season kicked off Friday as celebrities and political scions flocked to the offices of the elections commission to file their nominations.

The process launches a typically noisy and deadly seven months of campaigning for more than 18,000 positions, with the Covid-19 pandemic and the economic downturn caused by lockdowns expected to dampen the party atmosphere.