Aha! Finally found the bit of Victoria’s Road Rules that I’ve been after for months. Paragraph 2, Rule 134, Part 11:
134. Exceptions to keeping to the left of a dividing line
(2) If the dividing line is a single broken or a continuous line, or a broken divided line to the left of a single continuous dividing line, the driver may drive to the right of the dividing line to overtake another driver.
So those obnoxious drivers in Haughton road, Oakleigh who squeeze past me nearly every day when there’s no oncoming traffic should be perfectly capable of pulling out and overtaking me legally.