MILAN (Reuters) - Nexi said it is happy to partner with UniCredit to help one of its biggest customers realize its ambitions in the payments sector, but the contract between the two groups is "solid" and any changes should benefit both.

UniCredit CEO Andrea Orcel initiated months ago a review of the bank's payments business for more unified management across the group's various markets, stoking fears among investors that this could lead to seeking new partners, to the detriment of Nexi.

Bernardo Mingrone, Nexi's Cfo, said during a call with analysts that the contract with UniCredit does not include the possibility of an early breakup.

"There is no option for either party to terminate this contract early. And so there are no fees to pay because there is no option, just to be 100 percent clear," Mingrone said.

Although the contract is "very solid" and long term, Nexi is "very interested in helping UniCredit achieve its ambitions in payments, which are growing," added Paolo Bertoluzzo, CEO of Nexi.

"Normally, if you end up signing a new deal on top of an existing, solid one, it is something that is considered beneficial for the company," he told analysts.

Orcel said UniCredit will provide details of its payments strategy when it publishes its full-year results.

The payments business is one of the few businesses that Orcel's predecessor, Jean Pierre Mustier, never considered, even though he sold assets worth about 13 billion euros to strengthen the bank's capital reserves.

In response to a question about whether UniCredit might divest its merchant acquiring business, Bertoluzzo said he would be "very surprised."

"They want to invest more in payments, not less," he said.

Orcel is trying to grow UniCredit's fee income, and payments is one of the few businesses that provide fees for the bank after Mustier sold asset manager Pioneer and Fineco.

(Translated by Enrico Sciacovelli, editing Stefano Bernabei)