Up to 200 children could miss out on free transport to school under an Education Authority (EA) review, it has been warned.
Eligibility for the EA's Home to School transport strategy is currently being considered.
The organisations said the measurement of the statutory walking distance was inconsistent across Northern Ireland, and it recommended that a consistent measurement based on gate-to-gate distances be introduced.
But SDLP education spokesman Sean Rogers warned that the changes could see the number of children eligible for free transport decline by as many as 200.
"This consultation aims to save money from home to school transport for children," he said. "However, the only solution presented by the minister is to lazily cut funding and services, meaning that 200 children each year will soon be ineligible to use the school bus.
"We are concerned that his proposal will come at the detriment to students from rural communities in particular, who have already been sidelined on this issue."
Mr Rogers said he was concerned that cuts could lead to more tragedies like that of eight-year-old Adam Gilmour, who died last year after being struck by a car while walking to school with his family.
"This death may have been prevented if transport, and specifically rural school transport, was up to standard," Mr Rogers added. "We should be working to improve this, not diminish it.
"Our response will call for savings to be made in more innovative ways than cutting services.
"Measures such as varying school starting times would mean increased services from fewer buses, providing for more children.
"The minister might forget how difficult it can be to get around without a chauffeur-driven car, but the hundreds of young children who rely on a bus to get to school know how important it is to keep that service going.
"We have a collective responsibility to stand up for them."
Mr Rogers said it was crucial that as many families as possible responded to the consultation and make their views known before it closes on January 4.
But a spokeswoman for Education Minister John O'Dowd blasted Mr Rogers' comment as "ill-informed.
"We are not running any consultation on the future of school transport at this time," she said.
"However, the EA is holding a consultation, and the SDLP has membership of the EA - a point Mr Rogers seems to have conveniently forgotten.
"If Mr Rogers has any constructive comments to make in regards to the future of school transport, he should submit them to the EA.
"The SDLP representative on the EA will be able to provide him with the address."