Speaking from beyond the grave in an interview broadcast on Saturday, the 79-year-old, who died of cancer in November, told Channel Nine he was spared the indignity of losing his mind and wanted to be buried vertically in a cardboard box with an oak he'd grown from an acorn at his head.

''Twenty years ago I was in Sherwood forest [in England] and I picked up an acorn. When I was at my last home, I planted it. It's now six foot tall. I want that oak tree to be put on top of me.''

Courtenay's rise from illegitimate South African orphan to brilliant Australian adman and best-selling author, famous for Louie the Fly and The Power of One, is well known, but in his goodbye interview Courtenay used his frankness to blast the government for its refugee policy.

''If I were king of the world, there wouldn't be boat people, there would be people coming in boats,'' he said.

Facing his imminent death, Courtenay said he was not religious and did not believe he would see his late son Damon again when he died.