sarahge

If so I have a question for you....

Why do Aussie bathrooms have a drain in the middle of the floor? Is it a building requirement, and if so why

The only reason I can see is so you have a direct route down to the sewer so all the smells can come up and pollute the air in the house

I've tried the water trap things and the things that look like a long thin funnel but neither seem to stop it. The only thing I've found that works is taping a plastic bag firmly in place over the top

Any ideas?

cresta57

It's a central floor waste, the vanity, shower & bath will all run into it. It shouldn't smell if you keep it clean as it's a water trap just like the "U-bend" under the sink in U.K homes.
If your house is an older one it could also be that it's just a small pipe that leads outside to a soakaway pit.