Parliament has passed the law change that extends the bright-line property tax from two years to five years.
The extension means profits from residential investment properties bought and sold within five years are taxable.
The previous government set the limit at two years.
Revenue Minister Stuart Nash put the change into a routine tax bill that was already going through parliament, avoiding the otherwise lengthy process of select committee hearings.
The bill passed its third reading on Tuesday night by 63 votes to 57.
Speaking during the third reading debate, the bill's final stage, Mr Nash said two years wasn't enough to stop speculators reaping untaxed gains.
He thought that extending it would help dampen the property market.
National's finance spokeswoman, Amy Adams, said her party would have supported the tax bill but for Mr Nash having put the bright-line extension into it.
"We can't support it because of the duplicitous way a stealth capital gains tax is being imposed on New Zealanders," she said.
"They didn't even allow the public the basic right to submit on it through a select committee."