Suspicions a Far North teacher may have been sexually abusing students should have been passed on to the Teachers Council at the time, the teachers' regulatory body says.
It has been revealed that James Parker, 37, the deputy principal at the rural Pamapuria School, south of Kaitaia, was investigated by police, the Ministry of Education and Child Youth and Family (CYF) in 2009 but no further action was taken.
This week he admitted nearly 50 charges of sexual offending against young boys after he was arrested in July, shortly after fresh complaints.
Teachers Council director Peter Lind says the council wasn't informed by either the school or police of the 2009 investigations.
It was "absolutely critical" such information was passed on - one of the key recommendations following a recent investigation into how a convicted child sex offender, Te Rito Miki, was able to work at a number of schools because of impediments to sharing information.
"We would expect to get notified by New Zealand Police on matters of this serious nature regarding a registered teacher," he told NZ Newswire.
Parker started teaching in 1999 and had been at one other Northland school but had spent most of his career at Pamapuria, Mr Lind said.
Police are still investigating the case and looking at Parker's teaching history.
Police and CYF both investigated children's complaints about Parker in 2009 but the allegations could not be substantiated.
Detective Senior Sergeant Kevin Burke, who's heading the current investigation, said police wrote a letter to the school in 2009 outlining their concerns.
He would not comment on the school's response to the letter.
The school's board of trustees has resigned and a commissioner, Larry Forbes, has been appointed. Principal Stephen Hovell is on leave.