Election officials say former Philippine President Rodrigo Duterte has been elected as mayor in his home city by a landslide, despite his detention by the International Criminal Court.

Former Philippine President Rodrigo Duterte was almost certain to be elected mayor of his home city by a landslide on Monday, unimpeded by his detention at the International Criminal Court on charges of murder as a crime against humanity.

A Philippine midterm election may have leaned in President Ferdinand Marcos Jr's favour but the stronger-than-expected showing for estranged vice president and bitter rival Sara Duterte may have given him a jolt,