The growing pressure for parents to work meant sending their child to school early was the only option for some parents, he said.
St Mary's Catholic School principal Ben Fuller said some students were dropped off at school before 8am.
Mr Fuller said the school was a safe site for students who were dropped off early but the morning start for teachers was an important time for them to prepare for the school day.
"From 8.30am students will be looked after and cared for within class but prior to that time we ensure our teachers have adequate time to prepare for the day," he said.
"We want to be able to cater to both parties but the time in the morning is essential for teachers to get ready for their kids."
Mr Fuller said prior to the doors opening at 8.30am, students are left to wait or play outside.
"If it's raining and a teacher sees kids are outside they'll let them in, we're not unkind about it."
He said early arrivals that became more frequent were taken up with parents.
The school attempted to start up a Before School Care programme, but Mr Fuller said the bid failed to gain momentum with parents.
"It's something that we've surveyed in the past but we didn't have enough numbers to justify."
Gate Pa School principal Richard Inder said a waiting room was arranged for pupils who were dropped off at school before it opened at 8.30am but there was no "direct supervision" until then.
A duty teacher was active by 8.15am but the morning time was needed for teachers to prepare for the day.
He said the bigger issue was students arriving late to school.
"If they arrive early that's great for them to settle in for the day but if students arrive too late they're at a disadvantage," Mr Inder said.
Over in Rotorua, NZME reported that some Rotorua children were being dropped at the school gates as early as 7am with some parents saying they had no choice but to drop their children off early because of inflexible work hours and before-school care being too expensive.