Stamp duty may be described as a form of tax that is imposed on various transactions generally referred to as "dutiable transactions". These include leases, mortgages, motor vehicle registration, transfers of leases, transfers of land, transfers of businesses and franchises, transfers of shares or trust units. Stamp duty, as with capital gains tax and land tax, is a highly technical area of law.

It is alarmingly easy for an untrained person to trigger a stamp duty liability and accordingly the possibility of stamp duty liability should always be considered before commencing transactions that may be dutiable. Like capital gains tax and land tax, there are concessions and exemptions from stamp duty.

On the other hand the law in this regard is most unforgiving and harsh penalties and penalty interest can apply if appropriate stamp duty is not paid on time. The amounts of stamp duty payable are often in the tens of thousands of dollars and sometimes in the hundreds of thousands of dollars. Dutiable transactions cannot be "undone" on grounds that the parties to the transaction did not realise that a stamp duty liability would be generated.