A court has heard a former Dilworth teacher hosted students at his Waiheke Island bach, gave them alcohol and abused them

Leonard Cave is on trial in the Auckland High Court for charges including sexual violation, indecent assault and supplying drugs to boys over several decades.

He's pleaded not guilty to all charges.

A former student told the court he caught Cave "in the act" of sexually abusing another Dilworth student at the bach, before being abused himself.