ROME (Reuters) - Italy intends to appoint Marcello Sala, head of an economy ministry department that manages state-run firms and asset disposals, as a supervisory board member at chip maker STMicroelectronics, three sources said.

The company, in which the French and Italian governments own a 27.5% share through a holding company, employs 50,000 people worldwide and has been facing a sustained downturn in its key automotive and industrial markets.

The proposed nomination, which once formalised must be ratified by the STMicroelectronics supervisory board and by the shareholders in a general meeting in May, comes as Italy is increasingly unhappy with the group's Chief Executive Jean-Marc Chery, one of the sources said.

The three sources familiar with the matter told Reuters the holding company would indicate Sala and Simonetta Acri as members of STMicroelectronics' supervisory board.

The supervisory board oversees policies followed by the board of directors and advises it.

Sala and Acri are expected to replace Maurizio Tamagnini and Donatella Sciuto, according to the sources, who all asked not to be named. STMicroelectronics declined to comment.

A close aide to Italy's Economy Minister Giancarlo Giorgetti, Sala has played a key role in helping the government deal with some of its most delicate corporate issues.

He supported the economy ministry as Italy cut its stake in bailed-out bank Monte dei Paschi di Siena to 11.7% from an original 64% through several share placements, in line with re-privatisation commitments agreed with the European Commission.

Current members of the STMicroelectronics supervisory board include Paolo Visca, who was head of staff at Italy's industry ministry when Giorgetti held that job during the government of Prime Minister Giorgia Meloni's predecessor Mario Draghi.

The Italian government wants to get a closer look at STMicroelectronics' plan to reduce its workforce as part of a $300 million cost-cutting programme. Italian unions have warned about more than 2,000 job cuts in the country.

Giorgetti and Industry Minister Adolfo Urso have summoned representatives from STMicroelectronics and Italian unions on April 3 to discuss the group's prospects in the country.

Sala will not resign from his job at the economy ministry in the immediate future, the sources said.

He is also among the candidates for the position of chairman at payments group Nexi, in which state lender Cassa Depositi e Prestiti is a leading shareholder, one of the sources added.

(Additional reporting by Nathan Vifflin in Gdansk, editing by Gavin Jones and Bill Berkrot)