Staff resignations more than doubled to nearly 20 per cent at the pesticides authority as a controversial push to move it from Canberra built momentum.
The figures emerged at an estimates hearing on Thursday as senators heard the beleaguered Australian Pesticides and Veterinary Medicines Authority struggled through May with a 15 per cent staff vacancy rate as it dealt with an influx of work.
Its rate of departing staff surged to 19 per cent in 2015-16 from 9 per cent the previous year as the Nationals promised leader Barnaby Joyce's New England electorate it would host the APVMA if it re-elected them at the 2016 federal poll.
Agriculture Department deputy secretary David Williamson confirmed that other towns had not been considered when deciding where to relocate the APVMA as the department was tasked with delivering on the Nationals' election promise - driven by Mr Joyce - that it would move to Armidale.
APVMA officials admitted the surge in resignations had dragged down its rate of on-time product approvals from 83 per cent in September to a historic low of 42 per cent in the March quarter.
Executive director of registration management and evaluation, Alan Norden, said it was realistic to expect the agency would take five years to rebuild levels of experienced scientists following the forced move north.
"It takes a number of years to bring up to speed new scientific people within our regulatory environment. It's not just understanding the science of what we do, but how that actually fits in with regulation of agricultural and veterinary chemicals as well," he said.
However, APVMA acting chief executive Stefanie Janiec said it was building staff capability and that a University of New England training program would reduce training times from several years to between eight to 12 months.
As the agency prepares for a full-scale relocation in 2019 it is using space at a Centrelink office in Armidale as an interim base, where it could use up to 15 desks as staff move and locals are recruited.
While the 200-strong agency has not decided how many staff members will work from Armidale when it moves, the APVMA expects it could base about 150 there and is deciding how to build a secure digital network for remote work by staff not moving to the northern NSW town.
Mr Williamson told senators the agency had started looking for a replacement for outgoing chief executive Kareena Arthy, who resigned last month, and that it may not fill her role until the end of 2017.
The APVMA registered only 30 per cent of new crop protection products on time in the March quarter, compared to 82 per cent six months ago, while the rate of veterinary medicine products approved on time dropped from 87 per cent in the December quarter to 58 per cent between January and March.