Mitrea, a Social Democrat Party Transport minister between 2000 and 2004, was also charged for taking bribes a year ago. He has denied both accusations.
"There are clues that he approved a land transfer from the Baneasa (state-owned) airport to a unnamed person, causing a 7 million euro loss," said Livia Saplacan, a spokeswoman for the anti-corruption department.
The new European Union member was praised by Brussels for anti-graft reforms carried out by the two-year-old centrist government after it started inquiries on several top-level politicians, including former Prime Minister Adrian Nastase.
But Romania could face sanctions from Brussels if it does not introduce an agency to monitor wealth amassed by politicians and show further progress by convicting high ranking criminals.
On Thursday, the Supreme Court suspended a corruption trial against Nastase after defence lawyers said the case was based on unconstitutional procedures.