MADRID (Reuters) - Spain's Naturgy has been placed under investigation regarding possible anti-competitive practices in the country's electricity distribution market, watchdog CNMC said on Wednesday.

The CNMC raided two Naturgy offices as part of the investigation, it said in a statement.

The watchdog will look into whether Naturgy electricity unit UFD "gave preferential and discriminatory treatment to incidents and complaints filed by wholesalers in 2021 and 2022 in detriment of other independent ones", the statement said.

The investigation's results are due within 24 months, it said.

UFD complies with all regulations in its dealings with wholesalers without favouring any, a Naturgy spokesperson said, adding the firm would cooperate with the regulator during the investigation.

The watchdog fined Naturgy 6 million euros ($6.45 million) in July 2023 for manipulating electricity prices in a specific market segment in 2019-2020.

($1 = 0.9305 euros)

(Reporting by Matteo Allievi; editing by Inti Landauro and Jason Neely)