Tax specialists are divided on plans by the Government to improve the fairness of social assistance.
The Government is proposing to introduce rules to include income from the likes of investment vehicles or fringe benefits when determining Working for Families tax credits, student allowances and community services cards.
The Crown intends cracking down on high earners unfairly claiming benefits.
But PriceWaterhouseCoopers chairman, John Shewan says some households are rorting the system, costing taxpayers tens of millions of dollars.
However, the Institute of Chartered Accountants says the changes are complex.
Tax director Craig Macalister says the may cost the Government more than it will save.
Submissions are due to close on 24 September.