The announcement was made by Hassan Nasrallah, Hezbollah's secretary-general, in an interview with Beirut-based New TV to be broadcast on Sunday.
Nasrallah said: "Contacts recently began for negotiations. It seems that Italy is trying to get into the subject. The United Nations is interested and the negotiations would be through [parliamentary speaker Nabih] Berri."
Massimo D'Alema, the Italian foreign minister, said on August 24 he did not know about any "secret" talks to free the captives.
But, Sergio De Gregorio, the head of Italy's senate defence committee, has said Iran, which backs Hezbollah, wants Italy to be involved.
He said Ali Larijani, Iran's national security chief, had told him personally that he would ask Hezbollah to negotiate with Italy.
The senator said on Sunday he expected the talks to begin this week.
He said the Israeli hostages were "still alive, fortunately", but declined to discuss their condition.
Hezbollah has been holding two Israeli soldiers since July 12. It caught them in a cross-border raid and wants to exchange them for some of the thousands of Arabs in Israeli prisons.
The operation led to a month of war between Israel and Hezbollah, which controlled large parts of south Lebanon. More than 1,300 people were killed, mostly Lebanese civilians.
Germany negotiated an exchange of prisoners between Israel and Hezbollah in 2004, and has said it is willing to play a similar role now.
"Germany also wants to be involved, so we should verify what [the situation] is, what will be decided on a European level," De Gregorio said.
The Israeli newspaper Haaretz has said Israel is willing to discuss an exchange.