The two former ministers were tried for treason and disclosing state secrets in a case involving strategic privatizations of state-owned companies.
In the same case, Stamen Stanchev was sentenced to five years and two months in prison and Vadim Benyatov was sentenced to four years and six months in prison for espionage.
Mihai Radu Donciu, former adviser to Nagy, was sentenced to five years in prison, and Mihai Dorinel Mucea, former deputy head of the office for privatizations OPSPI, was sentenced to four years and six months.
The trial in the privatizations case started in April 2007.
Seres was also sentenced to four years in prison in March 2014 for accessory to abuse of office in a case involving the defrauding of state-owned hydropower producer Hidroelectrica. That sentence is not yet final.