The charge carries a maximum penalty of a $250,000 fine.
Yesterday, Mr Yule said Uetaha's family and the driver had been informed of the council's change of plea.
"This was an absolute tragedy. A young boy lost his life and a good council employee had his career end in a very sad way.
"All you can do is look to prevent something like this from ever happening again."
He couldn't comment further while the case was still before the courts or speculate whether the sentencing judge would order reparation for Uetaha's family.
Ross David Pollock, the driver of the tractor, pleaded guilty last May to driving a vehicle dangerously and on July 11 was sentenced to six months' home detention, 100 hours' community work, disqualified from driving for three years and ordered to pay $5000 reparation.
The senior driver, who and been with the council for 13 years, expressed his regret and was "full of sadness" during his sentencing, after retiring from council duties a month earlier.
Later, Pollock, who had no previous convictions and a clean driving record, successfully appealed the period of driving disqualification imposed.
The three years' disqualification was quashed and a period of 18 months' imposed in lieu.
In a statement yesterday, the council said it is fully committed to providing a safe workplace and the safety of the public is absolutely paramount and "deeply regrets" the tragedy.
Since the incident, the council said it has reviewed its safe operating procedures for all mowing operators and improved the training and supervision of drivers.
"Safety protocols are more clearly explained ... and all mowers are instructed to leave a clear radius of 30 metres."
