The wheels on the bus go round and round, but not for Northland MP and New Zealand First leader Winston Peters who was stopped from getting on board a school bus.

Mr Peters says he was invited to visit Mangakahia Area School by parents who have been campaigning against the effect of dust on their children from the unsealed roads.

But he claims the Ministry of Education told the organiser at "the last minute" to not let him on board the bus.

"While we understand that there are safety issues of just anyone travelling on a school bus, it was important to be on the bus with the kids to see how the dust affects them," Mr Peters says.

"The Ministry informed the organisers at the last minute so we have to question what interference there has been at high levels in the decision making."

Mr Peters accused National of trying to stop him doing his job as a constituent MP "and at the same time, prevent Northlanders from raising serious issues and demonstrating the problems".

The dusty roads have long been an issue in the area, with National's Whangarei MP Dr Shane Reti accused of blackmail for trying to keep the issue quiet until after the Northland by-election.

Mr Peters has asked for Education Minister Hekia Parata to explain what happened.

Associate Education Minister Nicky Kaye says she was told yesterday about Mr Peters' planned trip, but told the ministry it was an operational decision.

"I fully support Mr Peters' right to view education services, it just needs to be done in an appropriate manner, I think they were only given 24 hours' notice, and make sure it is done in a safe way.

"This is not a political decision," she says.

The Ministry of Education says Ritchies, the transport agent for Whangarei and the North, had health and safety concerns about Mr Peters' intended trip so the ministry told them to give it a red light.

It says under Ritchies contract, they can't carry adults or other ineligible passengers without permission. The 20-seater bus is full with primary and secondary-aged students.

"Our transport agent advised us that carrying Mr Peters and other adults in his party would place the company at risk of exceeding the limits of the Certificate of Loading and could mean not all children would get seats.

"As this request was made at such short notice, it wasn't possible to ensure that we could ensure the health and safety of the children on the bus under these circumstances," the ministry says in a statement.

However, given more notice, the ministry says it would be "able to explore" what how it could accommodate Mr Peters' request while still ensuring the safety of students on board.

Newshub.