Zarate is currently on loan at the club from Qatari outfit Al-Sadd.
“Mauro wants to stay, he feels really good at Lazio and has no intention of quitting,” Luis Ruzzi told Gazzetta dello Sport.
Zarate has also been linked with a move to Spanish giants Real Madrid.
“Real have never made contact with us,” he added.
“(Lazio president, Claudio) Lotito has assured us that he will use the option to sign Mauro next summer and we have no reason to doubt this.
“Mauro has a contract with Lazio until June and he will remain here for a long time providing Lotito keeps his promises.
“I believe he will stay because Lotito always keeps his promises.”