"He created it as a continent far, far away where he could house all his experiments that had gone wrong," Clarkson wrote in a column for British tabloid The Sun.
The host went on to list several of these "experiments", including the saltwater crocodile, the redback spider, many snakes, and an "otter with a beak" - referencing a platypus.
"He needed a home for all these things, so he made Australia.
"And to make sure people didn’t go there, he put a huge coral reef on the approaches and filled the interior with a sea of sand that goes on for ever."
He said Australia and its experiments went unnoticed for years until Captain James Cook came along and "now the world knows all about Oz and its stupid, dangerous creatures".
"Plainly, God is embarrassed. Because he's decided to set fire to it."