His drink-driving offending had continued to the present day and he had received every sentence the court could give him except for home detention or prison.
Mr McGahey said police disagreed with Westerman's pre-sentence report which assessed his likelihood of re-offending as low, and said he believed the risk of Westerman re-offending was medium to high.
"This is a gentleman that's unwilling to change or incapable of doing so and he'll continue to be a risk on the roads. To fully accept what he's done, the appropriate sentence is probably imprisonment."
Judge Weir commented that Westerman had written a letter to the court which showed real remorse.
He also noted that Westerman's first four drink-drive convictions occurred between 1976 and 1996, and then there had been a gap until 2008.
He convicted Westerman and sentenced him to four months' home detention and 200 hours' community work, along with a warning that there would be no further indulgence from the court if he appeared again. Westerman was also disqualified from driving indefinitely.