If I enter Visa exempt (Oz pport) to Bangkok then go to Laos for a week what do I do about reentry,,?  Thanks

Get another Visa Exempt when you re enter Thailand.

If you're going to Laos by land, you can do that 2 times in a year and come back to Thailand visa exempt.  If it's by air, there's no limit. 

 

But in both cases (and always), it's at the discretion of the immigration officer.  I'm assuming the OP doesn't have a history of living in Thailand, or black marks (like overstays) on his passport.

 

Thanks guys