TUA Assicurazioni, a non-life company founded in 2003, is valued at around 300 million euros ($335 million), according to the sources. TUA offers policies covering areas such as motoring, home and health and was acquired by Generali as part of its deal to buy smaller rival Cattolica two years ago.

Two sources mentioned German insurance heavyweight Allianz, fellow German insurer Talanx and France's Groupama as potential bidders.

One of them also named Italy's Itas as one of up to five parties that could bid in the second round.

Talanx could however drop out of the reckoning if it wins an auction for the sale of the insurance business of the Italian cooperative banking group ICCREA, the same source said.

ICCREA is expected to pick two insurance partners by the end of the month. Talanx has expressed interest in ICCREA's non-life business and is competing with Swiss Helvetia Group, Groupama and Italian cooperative insurer Assimoco.

Generali, which is being advised by Rothschild and Mediobanca, kicked off a second phase of the sales process earlier this month, opening TUA's virtual data room to potential bidders.

Generali, Rothschild, Mediobanca, Talanx, Allianz and Itas declined to comment. Groupama did not reply to an emailed request for a comment.

($1 = 0.8946 euros)

(Additional reporting by Gianluca Semarero in Milan, writing by Keith Weir; Editing by Keith Weir and Louise Heavens)

By Amy-Jo Crowley and Valentina Za