Beef + Lamb New Zealand's Lamb Crop 2016 report says the average lambing percentage across the country was up 2.1 percentage points - a remarkable performance given the challenges of the previous season.
The average lambing percentage was 123 lambs per 100 ewes and it was achieved because ewes were in good condition, there was enough spring feed, and more lambs were born from hoggets.
B+LNZ Economic Service chief economist Andrew Burtt said the report estimates 23.7 million lambs were tailed this spring.
They came from a breeding ewe flock that was down 3.1 per cent on last year.
"The smaller ewe flock occurred with the shift towards cattle production and the impact of facial eczema in North Island regions.
"Farmers read the climatic signals and made decisions early and the lamb crop result reinforces the impact of those management decisions."
In North Island regions, lamb numbers were affected by the impact of facial eczema on breeding ewe condition and numbers, and wet climatic conditions which hindered lamb growth rates," Mr Burtt said.
Lamb numbers in South Island regions were slightly ahead of last season, due to good climatic conditions, improved lamb thrift and a lift in ewe lambing percentages. These factors combined to offset a decrease in breeding ewe numbers.
Mr Burtt said over the whole country, there was a 1.3 per cent drop - or 0.3 million fewer lambs than last year.
In the North Island, 11.3 million lambs were tailed - down 0.3 million on last year, but up on 2013's tally. Meanwhile, 12.4 million lambs were tailed in the South Island.