Sergeant Kevin Milne, of Kawakawa police, said one victim had complained immediately. The other, however, laid a complaint only after a witness reported seeing another incident and police managed to track her down.
"We're mindful that if there's one person who didn't report it initially, there may be more. Anyone who has experienced anything inappropriate should contact North Shore police. They're also welcome to contact their local police station," Mr Milne said.
The initial complaint was made in Northland but the accused was arrested in Auckland as he was about to board another bus, so North Shore police were handling the investigation.
• Anyone with information that may help the enquiry should contact Constable Anthony Corbett of the North Shore CIB on (09) 477 5000 or email anthony.corbett@police.govt.nz.