Police have charged an anti-lockdown protester after an unauthorised protest in Sydney last month.

The 39-year-old man was arrested at a home on Watergum Way at Woonona, charged with riot, assault police, two counts of throwing a missile at a police officer at public disorder.

Police allege the man participated in the unauthorised protest in Sydney CBD on July 24, during which he allegedly threw horse manure and a pot plant, hitting a mounted police officer and her horse.