A mother of two says children travelling on school buses in rural areas with no seatbelts is a fatal accident waiting to happen.

Two children were seriously injured and six others suffered minor injuries after a school bus crashed near Murchison this week.

Murchison Area School principal Andy Ashworth says the bus was taking children home when the crash happened and was in an area with little signal.

Last week, four school students were injured after two buses crashed in Christchurch.

St John clinical director Dr Tony Smith says ambulance officers are often the first to arrive at the scene and see first hand the devastating impact of crashes, especially when passengers are not wearing seatbelts.

"Our view that seatbelts on buses of an agreed definition should be compulsory remains unchanged; we believe safety belts should be worn to prevent fatalities and serious injuries including fractured and amputated limbs."

In 2018, St John urged the government to make wearing seatbelts compulsory on some bus services after two people died and many others were injured in a spate of accidents - but the calls fell on deaf ears.

In 2011, 35 students were injured when a logging truck slammed into the back of a school bus in the Bay of Plenty.

Then transport minister Steven Joyce said he needed more information about the crash before considering whether seatbelts might be needed on buses.

The Ministry of Transport says buses are not required to have seatbelts because buses are far safer than any other mode of road transport.

Manager of mobility and safety Helen White says about 100,000 children in New Zealand travelled to school by ministry-funded bus services every school day.

Travelling to school by bus is much safer for children than travelling to school by car.

A 2015 report by the NZTA found that passengers in cars and vans are seven times more likely than bus passengers to be killed or injured in a crash.

White says while seatbelts are not mandatory for buses, increasingly new buses used for tour and long-distance services are equipped with seatbelts.

Waitaki Valley resident Pip Cameron, who lives on a farm in Otematata, says her eldest daughter started school a couple of years ago, and when she enquired with the local bus company if there were seatbelts on the school bus, the answer was no.

Her daughters go to school in Kurow 30 kilometres down State Highway 83.

"My oldest wasn't the legal height to be in a car without a booster seat so I was wondering how she was able to sit in a bus seat let alone without a seatbelt.

"Until we can see a change I'm not comfortable allowing my children to be in a massive bus without a safety constraint going 80km/hour down country roads where there are always big trucks and milk tankers whizzing by."

Cameron drives her girls to school every day and says she will continue to until changes are made.

Hearing that more children have been injured this week in bus crashes is gut-wrenching for Cameron, who has been campaigning for seat-belts on buses for over a year now.

"Do we have to wait for another death for people to take this seriously, no one likes to hear about a child dying on our roads.

"I have written to the prime minister, the local MPs, the transport minister and the ministry, but I just get generic replies back saying that not much is going to happen."

She says her family is not the only one with concerns.

"I think when the ministry talks about children being safer in buses than in cars they are talking about our cities where buses are travelling 40-50km/hour with lights and more traffic controls not the kids on our rural roads - you can't really compare the two.

-RNZ.