A boy who has been barred from a school bus by a 117-year-old distance rule has been told to apply for an ACC-funded taxi instead.

The decision will cost ACC at least $2300 a year if it agrees to fund a taxi, even though the boy's parents say there are empty seats on the school bus that goes past their gate on Inland Rd, 3.8km from his school at Kaipara College in Helensville.

His father, Matt Hepper, slammed the decision as "bureaucratic lunacy".

His son Ethan, 13, caught the school bus to primary school, but no longer qualifies for it this year because he has now started at college.

A rule dating back to 1904 provides free school buses for primary school students living at least 3.2km from the nearest school, but for secondary students only if they live more than 4.8km from school.

The Heppers applied for an exemption from the rule because of a head injury Ethan suffered in a dirt bike accident two years ago.

But Kaipara College principal Steve McCracken has told them that the Kaipara Transport Network, which operates the school bus, declined to grant an exemption because Ethan is "eligible to apply for transport assistance through ACC".

"I would encourage you to pursue an application through ACC and our student support team will be able to assist you with that," McCracken told the family.

"Should, for any reason, that application be declined, I would be able to take the dispensation request back to the KTN for further consideration."

Hepper said the decision was ridiculous.

"We obviously don't want to waste taxpayer money like this, when a perfectly good half-full school bus stops at our driveway anyway, but it is a perfect example of the bureaucratic lunacy that this country is plagued by," he said.

He said a taxi fare calculator website showed that a 3.8km taxi trip would cost $6.10 each way, or $2318 allowing for two trips a day over the 190 days in the school year.

But he said the cost would almost certainly be much more than that because no taxis were based near their home so would probably have to come from West Auckland or the North Shore.

The Heppers and other rural families in the area feel it's not safe for their high-school children to walk to and from school on a winding metal road with many blind corners.

Instead, Ethan's parents drive him to school each day and Hepper, who runs his own building business in Ōrewa, leaves work at 2.15pm each day so that he can pick Ethan up from school and take him home.

Another local parent who has started a Facebook campaign on the issue, Louise Clunie, pays her father to drive from Helensville to pick her children up in the morning, drive them to school, drive them back home at night and then drive back to town.

"This comes at a time when the Government is trying to discourage the use of cars due to pollution and global warming," she said.

But McCracken said the Kaipara Transport Network had to stick to the rules because hundreds of other families are also barred from school buses because they live within 4.8km of the college.

"If we allow students on who are 3.8km from the school, that has huge financial implications - allowing 3.8km for the rest of the area, we're talking tens of thousands of dollars," he said.

The school transport rules do not allow exemptions from the 4.8km rule if students are on ACC.

Hepper said the family had met ACC regularly since Ethan's accident and would discuss a taxi service at their next meeting.