Police did not detail the alleged crimes but the victim, an 18-year-old who cannot be named for legal reasons, recounted his ordeal to Fairfax New Zealand earlier this month.
He claimed a group of men assaulted him in a basement after an argument over a prank telephone call, punching him and forcing him to eat bongo chilli peppers.
The chillies, cultivated in Fiji, reportedly measure 100,000-350,000 Scoville heat units, compared to 3,500-8,000 for a jalapeno.
The teenager said he ate one but could not finish a second and was punished with a punch in the head.
“My insides were hurting, sweating, and I couldn’t see anything or even talk properly,” he said.
“Everyone was just laughing and watching.”
He said a man then pulled down his pants and grabbed his genitals. Police launched an investigation after he told his mother about the alleged sexual assault the next day.