Charities have been spared from tax changes in this year's Budget. 

Finance Minister Nicola Willis has been proposing revisions to tax rules that could see charities taxed on their business activities. 

But she says there are still complex issues that need to be worked through before any rules are updated. 

Tax expert Geof Nightingale told Mike Hosking it's likely too hard. 

He says there's been several goes at this over the last 20 years, with not enough tax revenue being the main problem. 

LISTEN ABOVE