BRASILIA (Reuters) - A five-member panel of Brazil's Supreme Court will vote on Monday whether to uphold Justice Alexandre de Moraes' ruling to shut down social media platform X in the country.

Moraes, whom X owner Elon Musk has labeled a "dictator," has called a virtual session of the court's first chamber - of which he is a member - so peers can review his decision.

Brazil's Supreme Court has 11 justices split between two chambers of five members each, not including the chief justice. They can vote to maintain or reject decisions by a single judge.

Justices Carmen Lucia, Luiz Fux, Cristiano Zanin and Flavio Dino sit on the first chamber alongside Moraes.

X was taken down in Brazil, one of its largest markets, in the early hours of Saturday following a decision by Moraes, who has been locked in a months-long feud with Musk.

The popular social media platform missed a court-imposed deadline on Thursday evening to name a legal representative in Brazil as required by local law, triggering the suspension.

The dispute over X has its roots in a Moraes order earlier this year that required the platform to block accounts implicated in probes of alleged misinformation and hate.

Musk has argued that Moraes was trying to enforce unjustified censorship and closed the X office in Brazil in August, without appointing a new representative. The judge has insisted that social media needs hate speech regulations.

Moraes' latest decision was backed by Chief Justice Luis Roberto Barroso.

"A company that refuses to name a legal representative in Brazil cannot operate in Brazilian territory," Barroso said in an interview with newspaper Folha de S.Paulo published on Sunday.