NSW Police have arrested a man after he allegedly made violent and offensive comments through a social media networking site.

Police alleged the 38-year-old sent violent and sexually explicit messages to a woman, posting them publicly on a social media site yesterday.

He was arrested at a home in Williamtown, near Newcastle, and was taken to Raymond Terrace Police Station where he was charged.

He was granted bail and will appear in court next month.

Police are continuing to monitor social media sites following the violent protests in Sydney's CBD.

They are reminding the public that any use of social media to incite violence will not be tolerated.