Stuart Cundy, who is organising the student's accommodation through Let's Homestay, said the quarantine was an overreaction to minor symptoms.
None of the students had been showing any signs of illness since leaving the airport, he said.
"I've been travelling with them for an hour-and-a-half on a bus and I haven't heard a sneeze.
"I think it's just an overreaction to some mild symptoms."
Mr Cundy said the group of 91 students were all being taken to Tauranga to be billeted with Kiwi families.
Earlier, passenger Lauren Borgas, 26, said she was 'red-stickered' by health authorities after sitting in a row of seats directly in front of the school group.
Men in white overalls and masks came onto the plane and eventually escorted all passengers into the airport.
Red-stickered passengers were taken into a separate room where St Johns staff took their temperatures and pulses.
Ms Borgas said when she was eventually cleared to join the other passengers in a gate lounge she was surprised to see the school group amongst them.
She said eventually a woman came into the room and told staff to remove the school group.
Her mother Rhonda Borgas was angry at the lack of information given to passengers and those - like herself - waiting on the other side of Customs to collect them.
She was still on edge about what her daughter may have been exposed to.
"If it was something really contagious it just proves we're not ready cope."
Earlier the Health Minister downplayed the situation.
Tony Ryall said it was unlikely the passengers had contracted anything worse than normal seasonal flu.
"We've been briefed on the situation, and advised that it is Japan's flu season, and there are no reports of new strains of flu there. We're keeping a watching brief but have been told there's nothing to suggest it's anything other than seasonal flu.''
- Herald Online staff with Newstalk ZB
