Updated 1.51pm: Growth in the New Zealand economy has been revealed to have been softer than previous thought, after a review by Statistics New Zealand on how it calculates its sums.

It's an accounting change that worked well for the National Government.

ASB Senior Economist Jane Turner says it's not a mistake - just a change in accounting practices to match international standards.

"It largely changes our interpretation of the past. It's been a little confused. Growth had appeared robust, but inflation pressures weren't picking up quite as we expected."

"We are still seeing a lift in growth, and that is important to keep in mind, but it is not as strong as we thought."

Statistics New Zealand's reported today that Gross Domestic Product is up 1% in the September 2014 quarter, bringing it to 2.9% for the year ending September.