Deforestation in the Brazilian Amazon reached near-record levels for the 12 months through July, according to newly released figures, the latest bleak news for the world's biggest rainforest under President Jair Bolsonaro.

A total of 8,712 square kilometres of forest cover - an area nearly the size of Puerto Rico - was destroyed from August 2020 to July 2021, according to satellite data from Brazilian space agency INPE's DETER monitoring program.

It is the second-worst year on record for the program's August-July reference period, behind only the 9,216 sq/km deforested the previous year - the worst for the Brazilian Amazon since the monitoring program was launched in 2015.

The latest annual figure is an increase of more than 90% since 2017-2018, the last full year before Mr Bolsonaro took office.

The far-right president has slashed environmental protection programs and pushed to open protected lands to agribusiness and mining.

Environmentalists say that is having a disastrous impact on the Amazon, a critical resource in the race to curb climate change.

"The rainforest's future is currently in the hands of land speculators, illegal loggers and gold miners," said Marcio Astrini, executive secretary of the Climate Observatory, a coalition of environmental groups.

"The Amazon has become a free-for-all for environmental crime, in partnership with the current government," he said in a statement.

Facing international pressure to improve his administration's environmental record, Mr Bolsonaro accepted the resignation in June of environment minister Ricardo Salles.

The regulation-slashing Salles, who was one of Mr Bolsonaro's most controversial ministers, is under investigation for allegations of involvement in a timber trafficking scheme.

The Climate Observatory said the new minister, Joaquim Leite, "has not yet made a single move to undo his predecessor's policies."

Two recent studies have found heavily damaged portions of the Amazon are now emitting more carbon than they absorb, a worrying sign the rainforest may not act as a curb on global warming much longer.

The DETER figure is for the period through 30 July, meaning the final number is likely to be slightly higher.