The union representing workers at AgResearch says its restructuring will cost the country agricultural scientists it cannot afford to lose.
AgResearch is moving 250 staff from its sites at Hamilton and Invermay near Dunedin as it concentrates its operations at Palmerston North and Lincoln.
The Public Service Association is warning many agricultural scientsts will leave the industry, or New Zealand, rather than relocate.
Public Service Association science committee chair Paula Scholes says it is the largest science restructure in a long time and will have a big impact on the quality of agricultural research.
She says many of AgResearch's scientists feel the restructure is going to be disruptive to research.
It will take significant time for AgResearch to rebuild if a large number of staff choose not to relocate, she says.
However, AgResearch chief executive Tom Richardson says staff have been brilliant throughout the restructuring.
He says they have been extremely professional and engaged with the process and have made useful suggestions about the restructure.