A 67-year-old man will appear in Parramatta local court on Wednesday facing 252 child sexual assault charges after being extradited from New Zealand overnight.

Upon arrival in NSW, the man was held and charged at Mascot police station and was refused bail, until appearing in Parramatta local court on Wednesday.

Detectives from Lake Macquarie Local Area Command were part of Strike Force Lozano, which was formed to investigate allegations of multiple child sexual assault offences during the 1970s and '80s at a school near Morrisset.

Lake Macquarie detectives commenced extradition proceedings against a man living in Christchurch, New Zealand, in November 2011. Last week the High Court of New Zealand approved the man's extradition.