The power to tax the new colonist of New South Wales was given to Governor Phillip. Remember New South Wales was a penal colony, so it seems a little convoluted that Governor Phillip would tax the new colonists, given that they probably didn't have the highest of incomes.
To add insult to injury, the first thing Governor Phillip did with the new tax revenue was build a prison. Ouch. Here's a crash course on Australian Tax Law