Department of Conservation staff have been forbidden from attending a Forest & Bird-initiated "bioblitz" on the Denniston Plateau.
The bioblitz will involve volunteers and scientists scouring the plateau to create a snapshot of its animal inhabitants and ideally discover new species, before a planned 200ha opencast coalmine goes ahead.
DoC staff had been advised by head office that it "would not be appropriate for them to attend the bioblitz", said Buller area manager Bob Dickson.
He had not received any negative feedback from staff about the directive.
DoC spokesman Rory Newsam said because one of the aims of the event was to encourage public pressure on DoC to decline Bathurst Resources' mining application, it was inappropriate for staff to attend, even in a private capacity.
"As public servants, it is inappropriate for DoC staff to be involved in an activity that forms part of a clearly stated campaign to change Government policy and we have simply reminded staff of this fact," said Mr Newsam.
"We follow the standards of the State Services Commission's (SSC) guidelines and we recommend our staff do that too," he said.
He believed DoC had issued the reminder only to its Buller staff.
Asked if they could lose their jobs by attending the bioblitz he said if staff breached the SSC guidelines then appropriate steps would follow.
If any new species were discovered on the bioblitz the discoveries would be treated like any other new scientific finding, regardless who made the discovery.
According to the Forest & Bird website, the event - in two weeks - is over-subscribed and registrations have closed.
Meanwhile, a DoC decision on whether the Denniston Escarpment Mine project can go ahead has been delayed.
The original hope was that a decision would be made early this year, but it is probably still some time off, said Mr Newsam.
Without a concession and an access agreement from DoC, Bathurst Resources will be unable to open a coalmine on public conservation land even if it wins an appeal against gaining resource consent.