MANILA - Presumptive President Rodrigo Duterte warned taxi drivers on Monday that refusing to give exact change to passengers is a criminal offense.

"It is extortion or illegal exaction," Duterte said during his first press conference after showing an unbeatable lead in the May 9 elections.

"Iyung mga taxi both dito sa Davao at Maynila, alam mo, kapag kinuha mo iyung kasi wala kang sinsilyo (change) at hindi mo talaga ibinalik, that is estafa. That is not a simple violation," he added.

Duterte also insisted that drivers who do not have loose change should not pick up passengers.

He also pointed out that drivers could always have their bills converted to smaller denominations at nearby stores.

The outgoing mayor of Davao City added that taxi companies should provide their drivers with loose change at the start of the day.

He also urged commuters to estimate their fare and give drivers the exact amount.