MILAN (Reuters) - Intesa SanPaolo (>> Intesa Sanpaolo SpA) is interested in buying Coutts International, the wealth management arm of Royal Bank of Scotland (>> Royal Bank of Scotland Group plc), a source close to the matter said as Italy's biggest retail lender seeks to expand into private banking.

The source, speaking on condition of anonymity, confirmed a weekend report in the Financial Times, adding that Intesa wanted to grow its asset management business for the wealthy in Switzerland, Asia and the United States as well as Britain.

Royal Bank of Scotland put up for sale the international arm of Coutts, founded in the 18th century and best known as banker to Queen Elizabeth, in August. One source said back then that the deal could net as much as $1 billion (0.63 billion pounds).

Flush with 16 billion euros ($20 billion) of excess capital and with interest rates at record lows, Intesa - like other Italian banks - is looking to boost profits by expanding in high commission-earning wealth management.

In Italy, it is looking at small private bank Cesare Ponti, owned by troubled lender Carige (>> Banca Carige SpA), although there have been no contacts so far, the source said.

Intesa Sanpaolo has offices in London and estimates that potential Italian clients in Britain number around 400,000. Besides Britain, Coutts has operations in Switzerland, Abu Dhabi, Dubai, Qatar, Singapore and Hong Kong.

A second source close to the situation said Coutts was in the process of sending out an information memorandum to potential buyers and expected first round bids before the end of the year.

The UK-based bank recently hired Goldman Sachs (>> Goldman Sachs Group Inc) to seek buyers for Coutts. Julius Baer (>> Julius Baer Gruppe AG), the Swiss private bank, expressed interest in September.

(Additional reporting by Matt Scuffham in London; editing by Alexander Smith and Susan Thomas)

By Gianluca Semeraro