Stirling Council employee Scott Hamilton (43), from Bonnybridge, is said to have reversed and struck Peter Willis in Dunblane, Stirlingshire in December 2014.
Hamilton faced an allegation of causing the pensioner’s death by dangerous driving today at the High Court in Glasgow.
His lawyer George Pollock entered a guilty plea to a reduced charge of causing the incident due to driving without due care and attention.
But prosecutor Allan Nicol told the court: “That plea is not acceptable.”
It means Hamilton will now stand trial in September on the death by dangerous driving allegation, which he denies.
The charge states the incident happened in Sheriffmuir Road, Dunblane on December 3, 2014.
Prosecutors claim Hamilton did reverse his vehicle without taking adequate steps to “ensure that it was safe to do so”.
He is also said to have done this without using the “Trained Reversing Assistant” provided to him. It is stated Hamilton then hit Mr Willis, who was in a motorised wheelchair at the time, and died of his injuries.
Judge Lord Burns set a trial due to take place in September in Stirling.