Italian Prime Minister Silvio Berlusconi's wife said she will seek a divorce, after years of public sparring with her husband over his public flirtations with women whom he has also drawn into his political ranks.

Veronica Lario, a former actress who married Mr. Berlusconi in 1990, plans to send him a letter on Monday informing him of her plans to file for a divorce, according to a person close to Ms. Lario.