Former Interior Minister Habib El-Adly was sentenced to five years, while former Finance Minister Yussef Boutros Ghali got 10 years in absentia and ex-Prime Minister Ahmed Nazif was given a one-year suspended sentence.
The three were charged with misusing public funds and unlawful gains valued at 92 million Egyptian pounds ($15 million), the official said.
Several years ago, Egypt changed the format of its vehicle number plates. The ministers, along with a German businessman, were accused of profiteering from a deal to import the new number plates, which they bought directly without a public tender as laid down by the law.
They also bought the number plates for higher than their market price.
El-Adly has already been sentenced to 12 years, then five years on corruption charges, and Ghali was sentenced to 30 years in a separate case.
The trials are part of a broad probe into corruption by the country's new military rulers who took power after President Hosni Mubarak was ousted by a popular uprising in February.
Authorities on Tuesday announced they will allow a television camera into court for the trials of Mubarak's associates to placate protesters calling for more transparency.
Judge Mohamed Hossam Al-Gheriyani, the head of the Egyptian Supreme Judiciary Council, said in a statement that one camera would be allowed into each session.
Images would be shown on a screen outside the courtroom. It was not immediately clear whether court sessions would also be broadcast on public channels.
Separately, the state news agency said Al-Gheriyani recommended moving the trials to venues that could hold more people.
Egyptians extended protests calling for swifter reforms into a fifth day on Tuesday. Protesters have been angered in part by the slow pace of corruption trials and closed court sessions.
Last week, a court cleared three ex-ministers of graft in the first ruling to exonerate such senior officials since Egypt's uprising.
The protests that unseated Mubarak in February were driven by anger at high-level corruption, and the trials of his former associates are regarded as a credibility test for the military council that took power after his downfall.
In one court hearing last month, some families and friends of the more than 840 people who died in the uprising were not allowed into the courtroom because of the number of lawyers, activists and journalists there. Scuffles broke out between security staff and those prevented from entering.
The large crowds had prompted calls for El-Adly's trial to be moved to a bigger location. Some newspaper commentators had even called for his trial to be held in a sports stadium.
