Finance minister Bill English has again taken aim at property investors who offset their tax by using losses in leveraged property.
The comments suggest that the government is looking ringfencing losses on property investment so they can't be used to offset personal income tax.
English claims the current tax system is unfair and inequitable and the Government will address this in the Budget.
He highlighted in Parliament how the current system can allow a household earning $100,000 a year, with two dependent children, to reduce the tax they pay from $27,500 a year to less than $10,000 a year.
"In reviewing the Tax Working Group's recommendations, the Government acknowledges the system needs to be fair and have integrity," he said. "This is most apparently not the case at present, where highly uneven tax rates apply between taxpayers with similar incomes."
English said a self-employed person earning $100,000 a year would normally pay income tax of more than $27,500 a year on the top marginal tax rate of 38 per cent.
But, in certain situations, the current system allowed them to significantly reduce their tax bill by, for example:
English says that at this point, the total tax paid, on income of $100,000, has fallen below $10, 000, which is an effective income tax rate of less than 10%.
"The example is not uncommon. The Tax Working Group found that 10,000 households were reporting investment losses while also claiming Working for Families credits. We are aware of tax advisers actively marketing schemes similar to this.
"The current system lacks fairness and integrity because of the way income is defined and because different tax rates have proliferated.
"In the Budget, the Government will make the tax system fairer by closing this type of loophole. We will make sure that taxable income more accurately reflects true economic income - and that the system is fairer to all taxpayers."