"I've had several conversations with him but he's not ready to play for Bulgaria again," the former Germany's World Cup winning captain told Kicker magazine on Thursday.
Last week, Matthaus, 49, said he would try to bring Bulgaria's all-time leading scorer back in the team for the remaining Euro 2012 Group G qualifiers.
"He gave me no reasons but for me the issue is settled for Berbatov and other players can now take their chances," Matthaus added.
Berbatov, 29, quit the national team in May citing fatigue and family commitments for his surprise announcement.
However, Matthaus, who has an uphill task to take Bulgaria to the Euro 2012 finals following back-to-back defeats against England and Montenegro in their opening two qualifiers, remains upbeat.
"It's like the Germany team before the 2010 World Cup," 1991 FIFA World player of the Year Matthaus said. "Ballack got injured, so Ozil and Khedira took their chances and are now at Real Madrid."
Matthaus's first match in charge will be on October 8 when Bulgaria visit Wales in Cardiff.
"We must remove the pressure from the players and give them back the pleasure of the game," Matthaus, who became the first foreigner to coach Bulgaria since 1966, said. "I'm convinced that Bulgaria will soon achieve good results."
