The accident claimed 10 pupils, five boys and five girls. Over 30 others were injured.
Joseph Musyoka and his wife Margaret lost a son and a daughter in the crash at Kanginga. Both children were KCPE candidates at St Gabriel Primary School.
“It is very painful to lose a child in such circumstances. It is even more painful losing two children. We are devastated,” said Mr Musyoka, a businessman in Mwingi Town.
His pain is shared by former MCA Bernard Munyasya, who lost his daughter, also a candidate.
Another parent, Tony Njoroge, lost his daughter Joy Wambui.
The children had come from an educational trip in Mombasa when a truck hit their bus in the 11pm accident.
A requiem mass for the victims will be held at St Joseph Seminary in Mwingi on Thursday.
Mwingi Level Four Hospital medical superintended Evans Mumo said three pupils and matron Esther Vala were still at the facility.
“They are responding well to treatment, but would need a few more days for observation,” said Dr Mumo.
The section of the road where the accident happened is steep, narrow and bent.
The driver of the lorry lost control before it hit the side of the oncoming bus.
Meanwhile, Machakos governor Alfred Mutua has announced that no school bus will be allowed on the road after 7pm.
He said any such bus found driving in the county past the stipulated time would be impounded and drivers arrested. A fine of Sh50,000, he said, would be charged before such vehicle was released.
Mutua yesterday said these measures were meant to address accidents involving school buses.
He said the road transport policy would be enforced by a special unit that would work in conjunction with police.
This came as Abdullah Hassan, the driver of the lorry that was involved in the Saturday accident, was charged with causing the death of 10 pupils through dangerous driving. He denied the charges and was released on a Sh1 million cash bail.