"It's a pity the NZIER don't leave their offices. It still says they [RSE workers] are low-skilled, low-value migrant workers."
The labour of RSE workers had spinoffs for the wider economy in terms of productivity, right through the volumes of fruit harvested for export, he said.
"They [RSE workers] are highly skilled, highly productive, and do the jobs New Zealanders can't, and won't, do."
The mood among Central Otago growers was "pretty sombre" following season beset by labour shortages, and the report had struck a nerve.
"Rather than expanding our workforce, which is not there anyway, this serves the opposite effect and it almost points the finger at the growers themselves - everyone is really disappointed.
"It's gut-wrenching."
The NZIER report says there is no proof that a large influx of short-term migration to fill labour gaps, including the workers who come from the Pacific each year, contributes to increasing New Zealand's productivity.
It also presents evidence that there are net negatives to such visa schemes.
The report states there is scant evidence available for the known effects so far of seasonal, temporary migrant workers on the economy, particularly horticulture.
However, it acknowledges technical challenges prevented the study separately identifying the implications of working holidaymakers and RSE workers.
The RSE scheme began in 2007 and allows horticulture and viticulture employers to provide seasonal jobs for workers from some Pacific nations.
It has since grown from 5000 workers a year to more than 14,000.