A Brazilian court has blocked an attempt by the president, Michel Temer, to open up swaths of the Amazon forest to mining companies after an outcry by environmental campaigners and climate activists.

The federal judge Rolando Valcir Spanholo said the president went beyond his authority in issuing a decree to abolish Renca, an area of 46,000 sq km (17,760 sq miles) that has been protected since 1984.

Approving an injunction requested by public prosecutors, the judge said the dissolution of Renca (more formally known as the National Reserve of Copper and Associates) could only be done by Congress.

But this may be only a temporary reprieve for the area, which is thought to contain deposits of gold, copper, tantalum, iron ore, nickel and manganese.

The attorney general has appealed. In several previous cases related to development of environmentally sensitive areas or indigenous territory, higher court judges have overturned rulings made by local courts.

But the injunction buys a little time for opponents and adds to the pressure on Temer, who has repeatedly come under fire for putting economic interests ahead of the environment.

The announcement of the abolition of Renca prompted a furious backlash last week. An opposition lawmaker called the move the “biggest attack on the Amazon of the last 50 years”. The supermodel Gisele Bündchen, who has become a prominent advocate of forest protection, has accused the government of selling off the Amazon for private interests.

Temer subsequently withdrew his initial decree, and re-issued it with a clarification on protections for indigenous territory and conservation areas. Environmental activists said the move was a marketing ploy, because 30% of the region would still be opened up to mining companies.