"The IRD will proactively be looking to contact people who have listed their houses for rent during the Rugby World Cup and reminding them of their income tax obligation to record all income in their tax returns.
"I am sure many New Zealanders have overlooked this consideration in deciding to rent out their houses."
But Mr Turner warned that the expenses able to be deducted could be much smaller than expected by those renting out their houses.
If a house was rented out for two weeks and lived in by the owner for the remaining 50 in a year, 96% of mortgage interest was non-deductible along with 96% of rates and repairs.
The IRD would still want its 30% of the income in tax payments.
People renting out their house for the cup should take care to both accurately record the rental income and ensure it was reflected in their tax returns.
They should ensure that all costs associated with the rental were also captured, he said.
While some costs would be "relatively easy" to capture - power, phone and cleaning during the period of the rental - others costs would be harder to define.
Issues might arise where expenditure was needed to be incurred before the rental, such as homeowners needing to bring the property up to the standard for the rental. In that case, those costs might relate solely to the rental and the taxpayer would need to decide whether the costs were capital or deductible.
Other costs could include having to recarpet the property where the carpet had been ruined during the rental period.
There had already been situations where taxpayers had been offered big rents for their properties during the cup and some had opted to find alternative accommodation while renting their property.
"While at first glance taxpayers are likely to suggest that the cost of the alternative accommodation is tax deductible as it is incurred to earn the rental income, in reality these costs are likely to be private as they are the cost of providing private accommodation.
"This will disappoint some," Mr Turner said.
