You are looking at a part of the Income Tax Act 2007 called 'Enactments repealed'. This means it is a list of laws that are no longer valid. The laws that are no longer valid include the Income Tax Act 2004. This is because of section ZA 1, which you can read about by following the link to s ZA 1. You will also see that some regulations are no longer valid. These regulations are the Income Tax (Withholding Payments) Regulations 1979. They were first made in 1979. The Income Tax Act 2007 has a list of these old laws and regulations that are no longer valid. This helps keep track of what laws are current and what laws are not. It is all part of the Income Tax Act 2007, which is a law about income tax in New Zealand.