2007年所得税法是目前所得税评估的法律。ITA 2007的BD1(1)规定，如果C部分满足金额，则为收入。收入的分类可以通过立法和判例法两种方式简化。CA 1涉及一个一般原则，如果它被立法确定为收入或在普通概念中满足，那么它就是收入。CA1(1)是判例法中根据不同案件情况而产生的基于普通概念的收入认定。
Taxes are classified as direct and indirect taxes, for instance, direct income tax is classified as 60% of the tax revenue. NZ income tax is significant according to the amount of revenue. It is the main resource of government revenue. In NZ, the rate of Income Tax is 10.5% up to $ 14,000, 17.5% for $ 14,000 to $ 48,000, 30% for about $ 48,000 to $ 70,000 and 33% for above $ 70,000.
A well-developed tax system is essential. It adheres to 3 principles, which are equity, efficiency, simplicity and it is aimed towards raising revenue, reallocating wealth and controlling economic activities (Theunissen, 2017). In New Zealand, only the parliament has the right to decide where and how to charge tax. The Income Tax Act 2007 has SBB1 stating that an annual tax act regulates the fixed rate on the taxable income for calculating the income tax. The amount calculated by the rates of taxable income is payable to the Crown under the Income Tax Act and the Tax Administration Act 1994.
Income Tax Act 2007 is the current act for income tax assessment. BD1 (1) of ITA 2007 states that if the amount is satisfied by part C, then it is income. The classification of income can be simplified by two ways, legislation and case law. CA 1 involves a general principle that the amount is income if it is identified as income by legislation or satisfied in the ordinary concept. CA1 (1) is the identification of income based on ordinary concept that was created in case law based on the circumstances of different cases.
Case law has testified that for examination of the circumstances that identify income, it is required to determine the characteristic of the receipts. If the items of receipts satisfy the primary or most income characteristics, then the item is classified as being an income.
Lord MacNaghten states in London County Council – v – Attorney General  AC 26 that income tax is tax on income, and it is not meant to be a tax on anything else. Tax assessment varies according to the nature of the source. NZ tax base has confirmed that once the income traction occurs, the income should be taxed as paying tax is the responsibility regulated by the law. The approach stated by Lord MacNaghten is likely to be scheduler approach. The standard of taxable income varies based on different nature of source. As per scheduler approach, the gains and receipts are separated, and each category has different rules to assess, collect and deduct the loss and expenditure.
In the current taxation policy of NZ, the nature of the source of income is regardless. The assessment of the tax is based on the source amount, called the global approach. Previously, NZ tax law was operational in net scheduler regime. From 1997, the global income tax has been adopted in NZ. Therefore, gains and receipts are combined with permissible deductions, irrespective of the type of income and the way it was incurred based on the tax rate of overall taxable amount.