The Forestry Corporation has defended carrying out daytime searches for an endangered, nocturnal glider before logging a NSW forest.
The Tallaganda State Forest, east of Canberra, is one of the last strongholds for the imperilled greater glider, which lost much of its habitat in the Black Summer fires.
The state-owned corporation has been logging in the area but was recently hit with stop-work orders after one of the animals was found dead near a harvest site.
The environmental watchdog says it lacks confidence in the corporation's efforts to identify den trees, which must be retained.
The corporation's pre-harvest habitat survey identified just one den tree but the Environment Protection Agency has since found 20 in areas earmarked for harvesting.
It's now emerged the corporation carried out its survey work during the day, when spotters would have been far less likely to see nocturnal gliders moving into and out of den trees.
A spokeswoman for the corporation said it had met all requirements and there's no stipulation that surveys must be conducted at night.
"It's called a broad area habitat search so they are searching for threatened fauna as well as flora ... they are not just searching for a particular nocturnal species," she said.
She said den trees were strictly defined and that meant someone had to physically see a glider entering or leaving.
While just one den tree was identified in the survey, she said another 5400 hollow-bearing trees would be retained in the forest and they might also be den trees.
But the EPA has hit back, saying the rules governing survey work don't list every single thing the corporation must do to comply with regulations.
"However, it does require them to plan, implement and undertake forestry operations in a competent manner, including to find and protect all greater glider dens with 50-metre exclusion zones," it said.
The matter remains under investigation.
Three conservation groups recently went into the forest and found 17 den trees over a small area, but their survey work was done from dusk into the night.
WWF-Australia, Wilderness Australia and South East Forest Rescue say hollow-bearing habitat trees aren't protected in the same way den trees are.
Den trees must be given a 50-metre exclusion zone but habitat trees can be left standing in an entirely denuded landscape.
