Mr Ostermann's biggest concern was keeping children safe before and after school.
The roads around Woodstock School were heavily congested and parents parked on broken yellow lines and across driveways instead of parking further away and walking in.
Teachers and some concerned parents patrol the school's two entrances - outside Fairfield Rd and Anson Ave - before and after school but no longer asked parents to move.
"We were formally doing that all the time and being polite and courteous in the way we were doing it.
"But the problem was we were being abused or ignored.
"Therefore we don't encourage our staff to approach anybody - just to take the registration number and supply that to police," Mr Ostermann said.
The parking problem escalated during winter when parents dropped their children off at the gates.
Some Hamilton schools have called in Hamilton City Council and police to help control the problem.
The council's parking enforcement staff patrolled outside schools at times but focused on educating parents and only ticketed vehicles as a last resort.
Staff also aimed to increase the number of pupils who walked or cycled to school by 10 per cent.
A neighbour of Te Rapa Primary School said cars blocked her driveway at least three times a week.
Two weeks ago she asked a driver to move so she could reverse out of her driveway and said the father was sarcastic and then beckoned her over.
"I felt very scared and very intimidated. It's not very pleasant," she said.
"It annoys me they think they can get away with it."
Hillcrest Normal School principal Irene Cooper said some days the school's property manager would stand outside the gate in a high-visibility jacket with a clipboard monitoring behaviour.
"Our parents say one of the biggest issues for them is parking in the school.
"But our schools weren't designed for you to come in and park, it's quite a novel idea. And if you went to school in Wellington you'd be paying for parking on the street."
The school had a roll of 560 students yet its drop off and pick up area hadn't grown since it had 350 children.
Pukete School issued reminder notices to parents who parked in the pick up and drop off area during peak times.
Hukanui School recently built a new carpark which had reduced the number of parents double parking or doing u-turn in driveways.
Waikato road policing manager Inspector Leo Tooman called it "chaos at the school gate".
He would like to see clear zones around the school gate for 50m to make the area safer for children.
He also urged parents to walk their children to school and couldn't understand why some people drove 300m from their home to the school when they could walk.
"My biggest concern is particularly a littley who can't see over the bonnet of a parked car, and goes to cross the road particularly if mum or dad is parked on the other side .
"Of course the potential there for a fatality is pretty high that's for sure," Mr Tooman said.
