You are not taxed 33% - that is the default resident withholding tax (RWT) which will comprise imputation credit of 28% and RWT of 5%.
You have to elect RWT rate at 0%, 10.5%, 17.5%, 28%, 30% or 33% - otherwise it is automatically 33%.
If your year end marginal tax rate is less than 33%, you will get some or all of the RWT back.
Hope that helps.