Riverhead quarry attacker Colin Mitchell was a serial rapist

It can now be revealed that Riverhead quarry attacker Colin Mitchell was also found guilty of raping a second woman in his trial.

Mitchell appeared in the Auckland High Court on Wednesday facing charges in relation to the February 2017 quarry attack.

He was found guilty of abduction, wounding with intent to cause grievous bodily harm and assault with intent to commit sexual violation. DNA evidence was presented at his trial showing he was the attacker.

Days after her attack, in an interview with police played to the court, the woman sobbed and told of her fear and shock.

Having earlier been drinking with friends on Karangahape Rd, she had no memory of how she had gotten to the quarry and was only jolted awake by a sudden hit to her head, she said.

Her dress already removed and feeling blood on her temple, she saw a man standing over her holding what looked like a baseball bat.

He demanded she turn around, but she refused and tried to talk him down, saying, "You don't have to be this person."

Instead, he kept hitting her and her next memory was scrambling away calling 111 with her phone, she said.

New rape charges revealed

Due to suppressions ordered by the court, Newshub was only allowed to report on these charges.

But it can now be reported he was convicted on another three charges relating to the 1992 rape of another woman, including abduction.

The 1992 victim told the court Mitchell beat her before assaulting her. Mitchell denied the charges, saying they had had consensual sex.

It can also be revealed Mitchell had previously been jailed for five years for the 1985 rape of a 26-year-old prostitute.

His latest victim says New Zealand needs to look at reducing sexually motivated attacks.

"For each individual with a rape conviction in New Zealand there are 99 other rape victims in New Zealand where the offender was not caught," she said.

"In 2014 British medical journal The Lancet published a report indicating sexual assault rates. Out of 56 countries New Zealand had the third-highest rate, more than double the world average.

"As important as addressing the causes of climate change, we need to ensure New Zealand is a place that we actually want our children, brothers, sisters and friends to grow up in."

Mitchell will be back in Auckland's High Court for sentencing on May 18.