MILAN, Aug 7 (Reuters) - Italian private equity fund Fondo Strategico Italiano (FSI) has agreed to spend 100 million euros ($110 million) to become the main minority investor in Bancomat, the country's leading cash card network.

FSI's latest investment in Italian payments sees the fund founded by former Merrill Lynch banker Maurizio Tamagnini strike a deal with some of Bancomat's main shareholders, and partner with sector leader Nexi, to develop the network, the companies said in a statement on Monday.

Bancomat, which provides debit card payments in virtually every Italian shop, is owned by 122 banks.

FSI struck its agreement with Intesa Sanpaolo, ICCREA Banca, Banco BPM, BPER and will buy into a reserved capital increase.

It did not disclose the size of its stake. Prior to the capital increase which will dilute its holding, Intesa owned 31.55% of Bancomat, according to its 2022 financial report.

While Bancomat is ubiquitous in Italian shops, its digital presence is minimal and under a new business plan, agreed by Bancomat, FSI and the main shareholder banks, the network will work to boost its online business.

Nexi will support this effort as a strategic partner for the development of the platform, the companies said in their joint statement. ($1 = 0.9109 euros) (Reporting by Valentina Za and Giulio Piovaccari, editing by Alvise Armellini, Robert Birsel)