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,

As results were still being tallied in Monday's Philippine mid-term election, impeached Vice President Sara Duterte released a statement just before midnight telling supporters the outcome was "not what we had hoped for".

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.