A Wellington primary school has suspended music lessons that used tutors without police background checks.
There are concerns a convicted sex offender may have been hired by the Wellington Music Centre, which uses school premises on an informal basis.
Island Bay School principal Deborah Fenton said there was no suggestion of any incident between an adult and a child.
The music centre said the man relieved as a teacher perhaps 18 months ago, and parents were always at the lessons. The school said whether parents were always present "will form part of the investigation of the music school".
The sex offender and the reliever have the same name but it is still to be confirmed they are the same man.
RNZ is in touch with the offender by email, but he has yet to confirm he worked at the centre.
The school said its informal arrangements with the centre do not meet legal requirements and it is changing them.
It has asked police to investigate.
"The Board is dealing first with the immediate risk posed by the lack of vetting," Ms Fenton told parents by email.
"Parents should note that anyone who has been teaching at the Saturday music school has not been through the Island Bay School police vetting process."
RNZ was given an anonymous tip-off that the music centre may have employed a man jailed until recently for several years for serious sexual offending against teenage girls.
The music centre teaches primary- and intermediate-age children.
Its organiser, Kathy Kent, said she was told last Friday about the matter and was "appalled" and "absolutely horrified".
In conversation with the reliever, it sounded to her that he was also doing private tuition, she said.
The centre has not responded to RNZ's calls since an initial on-the-record conversation.
The school board was expecting police to investigate whether at anytime a convicted sex offender was associated in any way with the Saturday music school, even as an occasional relief teacher, Ms Fenton said.
Police checks a legal requirement
The Children's Act 2014 brought in strict laws for safety checks including a police check and photo identification, by any organisations teaching children.
The Wellington Music Centre says it is Ministry of Education subsidised. The ministry said it required services which it funds to have a Child Protection Policy and to safety check any worker.
In her email, Ms Fenton told parents: "Music teachers have been managed informally rather than as formal employees.
"We now understand that the school was wrong to take that approach and that standard employment provisions should have been in place.
"In future, lessons at the music school will not occur with any music teacher until we have undertaken police vetting of that person.
"This is a legal requirement. The informal procedures we have been working under for years do not meet the legal requirements."
The school has reported the matter to the Ministry of Education, obtained legal advice and advice from the School Trustees Association.
RNZ asked the centre for contacts for the relief teacher but Ms Kent said she did not have any. The school said that in future, full employment records will be kept.
The Education Ministry said the school told it on Wednesday what had happened.
"Nothing is more important than the safety of our children and young people," Katrina Casey, Deputy Secretary Sector Enablement & Support, said in a statement.
"The school has taken immediate action and suspended music centre lessons until police vetting is completed.
"The school has taken the issue extremely seriously."
It had confirmed that all regular teaching staff and parents on school camps had been police vetted. The school was working with the School Trustees Association to review all its policies and procedures "to ensure this cannot happen again. In addition the NZ Police have provided advice to the school", the ministry said.
"Off the back of this incident we will be reminding all schools through our school bulletin of their legal obligations, we'll also be contacting our providers and suppliers to remind them of their obligations."
The ministry did not answer RNZ's questions about what this meant for its funding of or contract with the music centre.
The Teaching Council said not all people who teach music were required to be registered as teachers, such as people offering private tuition.
"The Teaching Council encourages anyone responsible for arranging for a person to teach music to children to make a safety assessment of the person, including verifying their identity and making background checks including a police vet and looking at the Register of New Zealand Registered Teachers," the council said in a statement.
"In some cases, such an assessment will be a legal requirement under the Vulnerable Children Act 2014, but in any case, it is best practice.
"We advise parents who are organising lessons for their children discuss with providers the policies they have in place to ensure child safety."