Five people have been arrested as protesters from the Reclaim Australia rally and counter-rally clashed violently in Martin Place on Sunday.

About 150 members of the Reclaim Australia group gathered in the city on Sunday morning, some wearing ancient Greek army costumes and others with Australian flags draped across their shoulders.

Two blocks away, a loud counter-protest group waved banners saying "Stand With Multiculturalism Against Racism" and "No Racism, no Islamophobia."