SAO PAULO, Aug 15 (Reuters) - The unexpected resignation of Eletrobras chief executive Wilson Ferreira Junior is likely to throw Latin America's largest utility into uncertainty and weigh on its shares in the short term, analysts said.

Ferreira tendered his resignation on Monday after less than a year in the role, leading shares in Eletrobras to dip nearly 4% on Tuesday. He was replaced by Ivan Monteiro, the former chief of state-run oil company Petrobras.

Some analysts expect Monteiro to maintain the Eletrobras strategy adopted under Ferreira, but his still not fully explained departure has raised doubts.

Ferreira was key in the privatization of Eletrobras, concluded last year when the government diluted its stake in the utility.

He first led the company from 2016 to early 2021, when he was appointed to oversee the privatization. After a brief stint at fuel distributor Vibra, Ferreira returned to Eletrobras in late 2022.

In a note to clients, JPMorgan analysts wrote that the Eletrobras statement announcing Ferreira's departure lacked details and prompted speculation as to why he would forsake a generous compensation package.

"We believe his departure is indeed due to personal reasons, but we cannot discard other possibilities," they said, including potential pressure from Brazil's new leftist government.

Earlier this year, President Luiz Inacio Lula da Silva's administration asked the supreme court to grant it voting power in Eletrobras proportional to its stake.

The government owns about 43% of Eletrobras' common shares, but shareholders are prohibited by law from exercising voting power greater than 10%.

Analysts said Tuesday's sell-off was not as strong as some feared, as Monteiro has the support of some investors.

In a statement, Itau BBA described him as a "well-regarded executive" who gained valuable experience as an Eletrobras board member. (Reporting by Leticia Fucuchima; Additional reporting and writing by Gabriel Araujo; Editing by David Alire Garcia and Barbara Lewis)