Labour Party's environment spokesman Eamon Gilmore has called on the Government to replace all school buses with custom-built vehicles.
According to documents released under the Freedom of Information Act, costs and not safety were the main reason for delays in the introduction of seat belts prior to the Navan school bus crash where five teenage girls were killed.
Officials saw no need to introduce safety belts or change the controversial three-for-two rule (three pupils to two seats) even though they acknowledged 11 students had been killed on buses in the previous decade.
Mr Gilmore said: "The only way to ensure the safety of children using the school transport system may be to transfer to a system of custom-built vehicles, as is the case in many other countries. These are vehicles, specifically designed for carrying children and including state of the art safety provisions."
Since the Navan tragedy Minister for Education Mary Hanafin has announced the scrapping of the three-for-two rule, although it appears that additional buses may not be available on time.
The documents reveal that as far back as 2002 officials were considering a number of cost-cutting options for the school transport system, including charging primary school children; increasing a school bus ticket by up to 30 per cent; getting rid of free tickets for children of medical card holders; and reducing some special needs services and ending others
Mr Gilmore said: "I believe that the vast majority of parents and taxpayers would say that no cost is too high to ensure the safety of children using the school bus system, but these documents show that the government had other priorities."
"The Education Minister's announcement of July 27th included provision for the acquisition of 20 such custom-built vehicles. We need to speed up this process with a view to full fleet replacement in due course," he said.