How did animals get from Noah's Ark to Australia?

God's Word says that the whole globe was covered in water at the time of Noah's Flood. All land dwelling, air-breathing creatures not on the Ark perished and the world was repopulated by those surviving on the Ark. That means that all of the animals and their worldwide distribution has taken place within a timescale of just over 4,000 years since the Flood. How can this be?