NSW's Forestry Corporation has been fined $45,000 and accused of blatant disregard for the environment after tearing down protected habitat trees.
The state-owned logging outfit blamed the destruction on the failure of mapping software.
But the state Environment Protection Authority found it continued to use the system despite prior knowledge of problems.
The fines relate to two breaches in two state forests in 2023.
At Nadgee State Forest on the south coast, 15 trees and other vegetation were destroyed inside an environmentally significant area.
Forestry operations were banned in that area to protect hollow trees that are crucial for wildlife.
The other offence happened in the Bagawa State Forest near Coffs Harbour.
In that case, the Forestry Corporation illegally removed a tree on a steep slope, breaching its obligations to prevent erosion.
Protection authority director Jason Gordon said forestry operations were subject to strict rules for good reason and the breaches showed "blatant disregard" for the environment.
"In no circumstances, should 15 trees have been removed from an environmentally significant area," he said.
"FCNSW claimed the Nadgee State Forest issue arose due to a mapping software failure, however our investigations found the software problem was known prior."
The general manager of Forestry Corporation's hardwood division said it was working to improve its boundary location technology.
"Unfortunately the technology failed to sync on this occasion," Daniel Tuan said.
He said another clump of trees was identified to make up for the ones that were destroyed, satisfying a requirement to set aside five per cent of the logging compartment.
Mr Tuan said staff had received extra training to avoid a repeat of what happened in Bagawa.
"Forestry Corporation apologises for not adhering to requirements prohibiting harvesting in steeper areas during the January to March period," he said.
"The error occurred when operations that were scheduled to be completed ahead of the January to March period were delayed and we sincerely regret this oversight."