More than a million people are expected to attend women's marches around the world on Saturday to demonstrate against sexism and sexual violence and call for women's rights following the inauguration of Donald Trump as the 45th American president.

A Facebook plea by a grandmother in Hawaii to march in response to Trump's election was credited with igniting the global movement, with more than 600 marches planned.

In a show of solidarity with the main march in Washington D.C., marchers will take to the streets of major world capitals such as London and New Delhi, and in far-flung spots from Macau to Mexico to Madagascar.