MANILA • The five main Philippine presidential candidates have faced off for the first time in a national debate, vowing to fight corruption and crime if they succeed President Benigno Aquino.

Sunday's televised debate was the first in a series aimed at focusing the contest on policies rather than the colourful personalities running in the May election.

But Mr Rodrigo Duterte played up his image of ruthlessness as he vowed to wipe out crime, illegal drugs and corruption in just three months by ordering the authorities to kill criminals.

The debate, held in Mindanao in the south, brought together the top contenders seeking to succeed Mr Aquino, who is limited by law to one six-year term.

Polls show the front runner is Vice-President Jejomar Binay, political kingpin of the financial centre of Makati. Tied for second are Mr Duterte and Senator Grace Poe, the adopted daughter of popular movie star Fernando Poe Junior. Mr Aquino's chosen successor, former interior secretary Manuel Roxas, trails behind them, with Senator Miriam Santiago in fifth place.

Mr Roxas took the offensive, stressing the need to maintain Mr Aquino's "straight path" policies that are credited with combating corruption and spurring economic growth. He also questioned Mr Duterte's temper, Ms Poe's experience and accusations of corruption that have dogged Mr Binay.

Such debates, however, do not necessarily play a pivotal role in Philippine elections, warned Ms Ana Maria Tabunda, research director of think-tank Pulse Asia.

"It will depend much more on to what extent candidates are able to get their presence felt," she said. "People will look at their personal characteristics."

AGENCE FRANCE-PRESSE