The Government has tightened the bright-line property rule which will affect people selling houses, other than their main home, within 10 years of purchasing.
The net gains made on the sale of the house within that period is added to the person's income and taxed at their top rate.
Chartered Accountants Australia and New Zealand (CAANZ) said the fine print of the law contained traps for owners with changing circumstances.
CAANZ New Zealand tax leader John Cuthbertson said people who were away from their main home for considerable periods might be caught by the bright-line test and would have to pay tax if they sold within the 10-year period.
"Homeowners should not assume that the main home exclusion will automatically apply to them for the full period that the property is owned."
A 'safe harbour' provision allowed homeowners to be away from their main home for a continuous period up to 365 days (12 months), which Cuthbertson said was too short to protect main homeowners in some circumstances.
"This coupled with a new change of use rule will result in more homeowners having to pay tax on a portion of their gain from their main home if sold within 10 years.
"If you fall outside the main home safe harbour, lots of paperwork and a potential tax bill lie in wait.
"Examples of where the main home exclusion doesn't apply won't be rare and, thanks to high house prices, the tax bills won't be small."
People seconded by their employer to another part of the country for more than a year could be caught by the provision, as could people planning to build their own home, he said.
"Taking more than a year from buying a section to actually moving into the newly built home could see homeowners caught by the rules for that initial period before they move in and if they ultimately sell within 10 years."
People expecting to be away from their home for more than 12 months should be keeping records of how many days they were living away from the property, as well as records of any capital improvements made which could be claimed against a property's sale proceeds, he said.
