A World Cup stadium being built in the isolated Brazilian state of Amazonas may not become a white elephant after all.

A judge in the area is proposing it be turned into a prisoner processing center after next year's world soccer showcase tournament.

Brazil is readying 12 stadiums for the World Cup, and several - including the new stadium in Manaus - will be little used after the event.

FIFA and Brazilian officials were the subject of widespread protests three months ago during the Confederations Cup, a warm-up for the World Cup.

Millions took to the streets to protest spending billions on sports events in a country with poor public services, high taxes and stark social inequality.

Brazil is spending an estimated $3.5 billion on stadiums for the World Cup, part of a total of $13.3 billion for related infrastructure needed to host soccer's biggest showcase.

Alvaro Corado, spokesman for the Amazonas state court system, told Associated Press on Tuesday that Judge Sabino Marques had proposed a novel idea.

"He would suggest to the government of the state of Amazonas that the stadium be used as a processing center for prisoners after the World Cup," Corado said.

Marques is also the president of a group that monitors the prison system in the state.

The new 44,000-seat stadium in Manaus, being built at a cost of $275 million, will host only four World Cup matches. The city of 2.3 million has no team in Brazil's first or second division.

FIFA requires only eight stadiums for the World Cup, but Brazil decided to have 12 - under pressure from politicians who used the construction projects to provide jobs and political loyalty.

Brazil Sports Minister Aldo Rebelo has defended the legacy of the stadiums as "centers for sports and non-sports events" and has suggested they would be places for conventions, shows and fairs.