In the latest case there is no suggestion of any offending at the school while he was volunteering.
One father was outraged at the news and the lack of consultation from the school.
"We've tried contacting the principal and they're ignoring us ... They've had a staff meeting this morning and were told not to talk to the media or anything else but we don't know what's bloody happening as parents," he said.
Principal Kataraina Nock yesterday refused to comment or say why parents had not been told of the arrest, which happened last week.
"The matter is with the police and if you want any information about it you should ring them. Other than that I have no comment to make."
The acting police area commander Counties Manukau South, Detective Inspector Dave Lynch, said the man had been under investigation since last year when the allegations were first made.
Nicholas Pole, deputy secretary, special education, said the Ministry of Education was notified about the allegations yesterday afternoon.
"The ministry's priority is the safety of staff and students. The ministry responded immediately by visiting the school and offering any necessary support."
He said the ministry did not believe the two cases were related.