The flu is hitting Rotorua schools with one report of 10 students away sick from a single class.
Rotorua Principals' Association president and Mokoia Intermediate principal Deborah Epp said they were hit hard at the start of the month but it was no worse than previous years.
"We had 10 children away sick from one class and five from another."
She said every school had to deal with the influx of bugs and flu during the winter months and most had good practices in place.
Mrs Epp said if a student had flu symptoms at Mokoia they would be sent to the school nurse who would send them home if they were thought to be infectious.
"The Ministry [of Education] monitor schools and has plans in place when epidemics break out.
"When the swine flu epidemic was going around [in 2009] we had signs on the classroom doors which said not to come in if you were displaying any of the symptoms listed."
She said during that outbreak they had 55 children away sick with flu symptoms.
Mrs Epp said this year was much better and she had not heard of any serious influenza break-outs at schools around Rotorua, despite the usual spread.
Lakes District Health Board medical officer of health Phil Shoemack said the risk of catching the flu at Rotorua schools could continue until the end of September.
"It's impossible to predict really ... but the flu generally peaks between early July and late September."
Dr Shoemack said they had not seen a decline in the number of cases being presented to local GPs.
"Personal hygiene is so important. We call it cough ethics for want of a better word. Just covering a cough and washing your hands goes a long way in preventing the spreading of bugs."
Dr Shoemack said GPs could not do much in the way of treatment for those with the flu but parents should still contact their doctor if they thought their child's illness was serious.
"You have to make a judgment call. But I would say if you are in doubt start by calling your GP to ask them what they think."
He said vaccinations were being offered free nationwide to over 65s and for those with serious medical conditions, until the end of August.
Owhata Primary School principal Bob Stiles said the flu was also hitting teachers, with temporary teachers in high demand in Rotorua. "We had three staff away last week with the flu."
John Paul College principal and New Zealand Secondary Schools president Patrick Walsh said there were not enough temporary staff on offer in Rotorua to cover the high demand, and occasionally other teachers had to pick up extra classes.
"Usually we would expect someone to be away for up to two or three days, but this winter it has been more like a week at a time. This includes students and staff."
Mr Walsh said the toughest thing was parents sending their sick children to school when they knew they were infectious.
"We can only send them to the sick bay because they are a high risk to infection."
Health Shop Rotorua spokeswoman Sharon Wickham said this was a relatively good winter. "It hasn't been so bad this winter with the sunnier weather.
"I think most of the schools have been able to let their children play outside rather than have them locked up inside all day, where the bugs spread."
She said preventative products for the flu, which were selling really well, included vitamin C, olive leaves, immune system formulas and herbs.