Brazil's environment agency, Ibama, has seen it's budget shrink by 25% since 1 January, when Jair Bolsonaro took office, according to internal government data collected by the opposition party, PSOL.
The data, shared with Reuters, also shows funding for prevention and control of forest fires has been reduced by 23%.
Brazil president Jair Bolsonaro has made no secret of his disdain for the public body, and has publicly rebuked Ibama as an obstacle to the nation's development.
New leadership at Ibama has also made it tougher for the agency to crack down on illegal logging, farming and mining that have despoiled nearly 12,000sq/km in the Amazon this year, former and current employees told Reuters.
For example, field agents have seen new restrictions on their ability to destroy heavy equipment found at the scene of environmental crimes, a long-standing tactic to slow land-grabbers, five of the people said.
In addition, an elite corps of Ibama forest cops has not seen action in the Amazon this year, a first since the heavily-armed, highly-trained unit was launched five years ago, according to four of the people familiar with the matter.
Instead, these special agents have been confined largely to desk duty, the people say, or assigned field tasks far from hot spots in the rainforest.
Punishment of environmental criminals has declined substantially on Mr Bolsonaro's watch.
Through 23 August, the number of fines issued by Ibama fell 29% compared to the same period last year, while the collective value of those penalties tumbled 43%, government statistics show.
Mr Bolsonaro's environmental policies have come under intense scrutiny in recent days as images of the burning Amazon have sparked international outrage and concern about the consequences for global warming.
Through July, destruction of Brazil's rainforest is up 67% compared to the same period a year ago, according to preliminary data released by the country's National Institute for Space Research.
Nearly 80,000 fires have been recorded this year through 24 August, the highest level since at least 2013, it says.
Environmentalists say Brazilian ranchers and farmers are intentionally igniting the jungle canopy to expand their operations illegally, emboldened by Mr Bolsonaro's pro-development,anti-regulation message.