You will most likely have seen the item on the news lately about IRD targeting cash jobs in some areas of Auckland and while IRD are concentrating on Auckland they will not be ignoring other parts of New Zealand and they certainly are looking at certain industries such as construction, hospitality and similar industries where cash payments are not unusual.
An example of this was highlighted in the Nelson Mail recently. A restaurant was sued for tens of thousands of dollars by IRD for significantly under-reporting income and failing to pay GST and Income Tax. The owners have been found guilty but haven’t been sentenced yet, we will update this when they have been.
And, don’t forget about Trade Me. IRD are keeping a close eye on those that buy and sell on Trade Me, so if you are doing this on a regular basis (regular enough that IRD consider it to be you are a business) then you should be declaring the income from sales and claiming the purchases and other expenses.