Found this on the web:

"FBVP, I have the definitive answer for you: Your "mystery song" is "Big Bruce" by Steve Greenberg, a minor hit here in the U.S. in the Summer of '69. The song is described in one of my music reference books as a "gay" parody of Jimmy Dean's huge #1 hit from the Fall of '61, "Big Bad John", so that explains the connection w/ that song. The Greenberg single was released on the Trip label here in the U.S., but I don't know about Australia, where you are..."