An estimated 100 million WhatsApp users in Brazil breathed a sigh of relief after the smartphone messaging app returned to service again on Thursday morning.

A judge had ordered the temporary blocking of the app's text chat and voice tools after the tech company, which is owned by Facebook, failed to comply with a prosecution order to disclose information relevant to a criminal investigation.

The suspension, which the court ordered internet service providers to enact, was meant to remain for until midnight on Friday but was overruled by a second judge in Sao Paulo after about 12 hours.

"It does not seem reasonable that millions of users are affected" by the ban on WhatsApp, said Judge Xavier de Souza, who recommended a higher fine be levied on the tech giant instead as Brazil's courts sought to pressure the company to cooperate.

The banning caused outrage in Latin America's largest country and even led to angry exchanges on the floor of Congress.

Court orders disregarded

In a statement referring to the ban, the city's state court system said that California-based WhatsApp had ignored two prior judicial orders this year and "because even then, the company did not heed the judicial decision, the public prosecutors' office requested the service be blocked."

One Brazilian television network, SPTV, said the shutdown happened after the smartphone app service failed to hand over communications linked to a probe into a gang that used the service to commit bank and ATM robberies.

Reuters said the suspension was linked to the arrest of a most-wanted drugs dealer.

Rush to resume service

On Wednesday, Facebook CEO Mark Zuckerberg took to his own social media site to say the firm was "working hard" to get the block reversed.

"This is a sad day for Brazil. Until today, Brazil has been an ally in creating an open internet. Brazilians have always been among the most passionate in sharing their voice online," he added.

WhatsApp's main competitors Viber and Telegram appeared to benefit hugely from the shutdown, each saying that 1.5 million new subscribers had registered during the 12 hour period.

Reports said users in Chile and Argentina were also affected by the block.

Reports suggest that Brazil's legal system has allowed single judges to block communications services in the past and Facebook and Google are among the many tech giants targeted.

mm/msh (AFP, AP, Reuters)