This year's lamb crop is the second smallest in nearly 60 years and the drought is to blame.
A lamb survey issued by Beef + Lamb New Zealand shows the number tailed is down by 4.7% to 25.5 million compared with last spring.
The drop of nearly 1.5 million from 2012 was not as low as earlier estimates based on scanning, which forecast two million fewer lambs this season.
Lamb numbers in the North Island, which bore the brunt of the drought, are down by more than 7%.
Beef + Lamb economic service chief economist Andrew Burtt says it means a lot fewer lambs for meat plants to process this season.
"As a result this year's going to be the third lowest in 60 or 70 years," Mr Burtt says.
Average weights are expected to be higher at 18.4kg, up from 18kg following the drought.
However, the increased weight would not make up for the decreased numbers, so the volume of lamb production for exporting will be down about 5%, he said.