He made a similar application a couple of weeks later which was also approved.
Mr Leith neglected to tell his boss that he was appearing on the same day as his friend, and that he was convicted for cultivating cannabis for his own use.
His boss became aware of the conviction only when he read about it in the Otago Daily Times the next day.
Mr Leith admitted that he had regularly smoked cannabis for some 30 years, but said he never smoked before work as he usually limited his use to Friday nights.
The company did not find Mr Leith's explanations satisfactory.
"Not only did [he] fail to see his cannabis consumption as an issue when driving trucks but when I asked [him] why he had lied to me before about why he needed time off work, [he] said he had not told me as he had 'done it before and gotten away with it'," the company's director told the ERA.
Before sacking him, the company said it was concerned about the potential danger to other motorists if Mr Leith were to drive under the influence, and the risk of prosecution the company faced if it knowingly allowed him to drive with a drug habit.
Mr Leith told the ERA he had not used drugs since starting work with the company, and that he had told them that he would be willing to be drug tested.
ERA member Mike Loftus said he preferred the company's evidence.
"Final confirmation the claim of abstinence was inaccurate comes in the form of a further conviction following the dismissal," he said.
Mr Loftus did not find the company's failure to provide a written employment agreement warranted a penalty because it was not deliberate impropriety.
