Germany's former World Cup-winning captain Matthaus replaced Stanimir Stoliov last week, saying he would try to persuade the 29-year-old Berbatov to change his mind and return to the team.
"Dimitar will not refuse to meet and talk to Matthaus but that's all," Berbatov's agent Emil Danchev told local media late on Sunday. "He will not return."
"He made it clear when he announced his decision earlier this year," Danchev added.
Berbatov, Bulgaria's all-time leading scorer, quit the national team in May citing fatigue and family commitments for his surprise announcement.
Matthaus has an uphill task to take the Balkan country to the Euro 2012 finals following back-to-back defeats against England and Montenegro in their opening two qualifiers.
The 1991 FIFA World Player of the Year's first match in charge will be on October 8 when Bulgaria visit Wales in Cardiff.
