Fire extinguishers, hoses, televisions and even a bronze bust of Mario Filho, the journalist after whom the stadium was named, were among the items stolen, the Rio de Janeiro Football Federation said in a statement on Tuesday.
"The worries over the present and the future of the stadium are only increasing," the Federation said.
The stadium, which underwent costly modernisations for the 2014 World Cup and the opening and closing ceremonies of the 2016 Olympic Games, has been unused since late last year with no-one taking responsibility for its upkeep.
Pictures published in Rio newspapers showed seats missing and the turf dry, worn and filled with ruts and holes.
O Globo said that windows inside the stadium were smashed, doors will not shut properly, and copper wiring has been stolen from walls and ceilings.
The Federation has arranged to meet with the city's clubs on January 17 to discuss what to do about managing the stadium, but its president said more urgent action is required or that meeting will be too late.
"If there is not an immediate government intervention to stop the looting and the destruction of the Maracana then it might not even be worth meeting on the 17th," Ruben Lopes said.
The ground, which also hosted the final match of the 1950 World Cup, was used by all of Rio's big four teams, Botafogo, Flamengo, Fluminense and Vasco da Gama, but has lain empty as clubs and authorities fight over who will manage it.