A blunder by Statistics New Zealand has led to inflation data rising at a faster pace in the September quarter than first reported.
The agency discovered it mucked up the way it calculated Accident Compensation Corp's motor vehicle licensing fees in the period.
The consumers price index rose 0.3 percent in the three months to the end of September, up from the 0.2 percent pace originally reported on October 18.
The annual pace was revised up to 0.4 percent, twice the 0.2 percent annual pace reported last month, and closer to the bottom of the Reserve Bank's 1 perc ent-to-3 percent target band.
"The changes were required to correct a manual processing error discovered by Statistics NZ. The error affected prices for vehicle relicensing fees, within the transport group," the Government department said in a statement.
"Statistics NZ is confident that the correction only affects the September 2016 quarter index numbers, as it occurred in our measurement of lower ACC levies for light vehicles that came into effect during the quarter."
The Government department has already told the Reserve Bank ahead of this week's monetary policy statement and the Treasury, which is preparing the half-year economic and fiscal update.
"Following our protocols for errors, Statistics NZ has decided to correct the CPI now to ensure our customers have the best possible information to inform their decisions," it said.