Gardyne, a former employee of Dundee City Council, carried out the offences while working at the local authority’s Contract Services department on Clepington Road.
The case has been continued without plea several times since September while the Crown and Gardyne’s defence agreed on the alterations to the charge.
Gardyne, of Smithy House, Auchterhouse, did not appear when defence solicitor Jim Laverty lodged a guilty plea on his behalf at Dundee Sheriff Court on November 16.
Sheriff John Rafferty deferred sentence for criminal justice social work reports and a restriction of liberty order to be prepared.
The case will call again at Dundee Sheriff Court on January 5.