The Taoiseach has ordered a "full systems overview" of Bus Eireann's fleet of school buses following a fire on Monday which destroyed a 17-year-old vehicle.
More than 30 teenagers escaped injury after the burst into flames near Athboy, Co Meath yesterday morning.
Speaking in the Dail this morning, Fine Gael leader Enda Kenny said parents were worried in light of up to three incidents involving Bus Eireann school buses in the past 12 months.
Mr Ahern said he did not believe that CIE engineers should check their own buses and he said he had asked Minister for Transport Martin Cullen to review the practice.
"It's not good practice nowadays to audit yourself in any procedure and I think it should be looked at. The entire process should be examined.
"I discussed it earlier with Mr Cullen and he will be ordering that this happens today."
Mr Kenny replied: "There is a fear you're going to have more of these. Given the nature of the five incidents we've had over the past 12 months, it is a cause of serious concern."
Mr Ahern replied that he understand that CIE was very strict on the road worthiness tests on school buses as it was conscious that they are carrying children.
Yesterday's bus passed a road worthiness test in an authorised test centre in Co Meath last August, he said. He added: "Maybe it's all perfect, but I would be certainly happier if it was looked at.
"We've had a number of incidents, people have lost their lives."
Mr Kenny later claimed that school buses were the most dangerous form of transport in the country when compared with intercity trains, the Dart, Luas trams and Aer Lingus planes.
Six people have been killed in five major incidents involving school buses in the past 12 months, he added.
He agreed with the Taoiseach that an independent safety assessment of CIE's school bus fleet should be carried out. "It is natural for parents to have grievous concerns about the safety of their children who use these buses.
"We've had enough warnings about school bus safety in just 12 months. We don't want to be still talking about it in another 12."