The Ministry of Agriculture & Forestry says foresters seeking carbon credits through the Emissions Trading Scheme have been driving much of the increase in new tree plantings.
MAF's estimates, based on reports from commercial forestry nurseries, show that 67 million seedlings were planted during the year to April. That's a 27% increase on the previous year.
MAF says that would equate to 12,000 hectares of new plantings on top of what's needed to replace harvested forest.
Sector policy director Iain Cossar says the incentive provided by the carbon market is one of the main contributing factors, but others are the comparatively high prices being paid for logs and MAF's own afforestation grants scheme and East Coast forest project.
However, the Forest Owners' Association thinks a recent dive in international carbon prices has changed the situation.
Chief executive David Rhodes says MAF's figures are from April, when carbon was fetching $20 per tonne. Since then the price has dropped to less than half that amount and, at that level, he doesn't think it is doing much for new planting.