The NSW government has been accused by the state opposition of launching "the single biggest attack" on the National Parks and Wildlife service since it was set up half a century ago.
Penny Sharpe, Labor's environment spokeswoman, used a NSW estimates hearing to press the government to confirm the loss of 49 park rangers - or 20 per cent of the total - since the coalition came to office in 2011.
The upper house member also asked the government to explain how the NPWS had seen its budget outlay slide from a projected $503.1 million in 2016-17 to a revised $448.1 million actually spent. That tally edged lower to $445 million in the current budget.
Anthony Lean, the chief executive of the Office of Environment and Heritage, told estimates the "bulk" of the reduction in spending was the result of a transfer of corporate services to other units.
"There's been a significant change in the way the numbers have been represented," Mr Lean said, adding he would take on notice a request to provide the proportion of the cuts.
A spokesman for OEH later told Fairfax Media that the removal of corporate costs accounted for the lower budget figures. Average staff numbers during 2011-17 were stable at about 1610 full-time staff equivalents, and these would rise to 1770 once the current restructure is complete.
Ms Sharpe, though, said the government continued to push through cuts, including so-called efficiency dividends of $5.6 million in the the 2016-17 and 2017-18 years.
"In its 50th year, the NPWS has never been so under attack because of cuts to staff, cuts to budget, and the sheer neglect of this government," Ms Sharpe said.
One example was the NSW National Parks Establishment Plan, originally earmarked for a review and update by mid-2014 to cover the 2015-2020 period, had now been pushed at least into next year, she said.
The government is planning to reopen the strategy for consultation to take into account the plan to provide more money to conservation efforts on private land as part of its biodiversity conservation overhaul, Mr Lean said.
The focus on private conservation meant "national Parks have gone to the back of the line," Ms Sharpe said.
The OEH spokesman, though, said the government remained committed to expanding the protected areas in NSW that now cover 7 million hectares.
Since 2011, the public reserve system had been expanded by than 70,000 hectares through the establishment of nine new reserves and 122 additions to existing reserves.
"It has also set aside $240 million [over five years] for the establishment of protected areas over private land as part of its biodiversity conservation reforms," he said.
Those reforms, though, were also a subject of Friday's estimates hearings, with opposition members questioning the reason for releasing new land-clearing codes for native vegetation before most of the maps had been finalised.
Those maps are intended to show which lands are considered to have high conservation value vegetation that will need approval from Local Land Services before it can be cleared.
Gabrielle Upton reiterated comments made last month to Fairfax Media that the maps were in addition to other codes and regulations already in place.
"There are strong penalties [for wrongful clearing] and a high level of monitoring of the reforms," Ms Upton told estimates.
Ms Upton also said she had "considered the advocacy" of the family of Glen Turner, the OEH compliance officer murdered three years ago while investigating land clearing by the Turnbull family at Croppa Creek, north of Moree. The new laws "will not diminish [Mr Turner's] work or his life", she said.
Ms Upton took on notice a question as to whether the land being cleared by the Turnbull family would have been approved under the new codes released on August 25.