The Ministry of Primary Industries is investigating a complaint about the school lunch programme.
New Zealand Food Safety's deputy director general Vincent Arbuckle said the complaint was that special dietary meals- such as those for students with allergies - were labelled for the wrong student.
The provider School Lunch Collective has admitted the error occurred at some Christchurch schools this month, that it's conducting its own investigation into the incident and putting in place extra checks so that it does not happen again.
Neither the company nor MPI will say which schools received the mislabelled lunches - though they have confirmed no students ate them.
Hillmorton High School was one Christchurch school contacted to put aside their special dietary meals on February 12 when the company realised a labelling mistake had been made at some schools, Principal Ann Brokenshire said.
"We were concerned there might have been [an error] given they had said they might have made some labelling errors.
"Of course, we didn't give those meals to the kids."
Brokenshire said staff from the School Lunch Collective came to look at the lunches and told the school these ones actually had correct labels on them.
"We waited until the (company) had checked it, it turns out they were too late to come and check it for the kids to get the food, so the kids missed out on lunch that day."
Brokenshire said some of the students which receive special dietary meals are those with food allergies, intolerances or cultural requirements with food.
MPI Food Safety Officers have met with the School Lunch Collective and visited a food preparation site as part of their investigation.
School Lunch Collective spokesperson Paul Harvey said the error was identified and rectified quickly - with the company calling affected schools and recalling the meals before it reached students.
He said the company is carrying out their own investigation into the incident and has provided MPI with an investigation report.
"Our kitchens are verified and audited regularly by independent MPI accredited specialists, and we follow the Food Act and Food Control Plans.
"We have put additional processes in place, including additional data checks, to mitigate any future dispatch errors."
Burnt, already-opened meals 'not a food safety issue' - MPI
MPI says it's also aware of an incident where school lunches arrived at a Whangarei school with the cellophaned lids of the packaging already coming off.
Whangārei Intermediate Principal Hayley Read said she had to order hundreds of pizzas when the spaghetti and meatballs meals arrived burnt, with the seals of the packaging already peeling off.
She said the Ministry of Education told her not to serve the meals as the lids being already opened made them unsafe to eat.
"There were about seven of us trying to dish out these meals, and as we were doing it we could see 'oh my gosh it's burnt, and it's unsealed.'"
"It's pretty shocking."
Arbuckle said MPI assessed this incident and considered there was no safety risk.
The meals had been outsourced by the School Lunch Collective to another company on that day, and reheating procedures had not changed the reflect different heating requirements.
He said foreign matter would not have entered the products because the lunches were transported in a plastic box.
"The issues evident in this case relate to the quality, rather than food safety, of the meals. As such, we are working with the Ministry of Education to ensure good process is in place so that meals are properly heated where necessary."
Ministry of Education's leader of operation and integration, Sean Teddy, said more of these spaghetti meals were delivered to Waikato schools.
"The seal on these meals also lifted when heated, however a safe alternative solution was put in place to protect them during delivery."
