Thammarak, a former defence minister, was charged with collaborating with two men to hire a member of the operations staff at the EC Office to change the EC database to state that the Nanachart Thai was eligible to contest the election. The EC official was given Bt30,000 by Thammarak, the court was told.
The court ruled that evidence showed that Thammarak did hire the official to tamper with the database so he was given the jail term without suspension. Thammarak can appeal against the ruling with the Appeals Court.
The court also sentenced the EC official to five years in jail.
The database tampering case is a fallout from the Thai Rak Thai dissolution case.
In 2007, the Constitution Court found Thammarak guilty of hiring smaller parties to contest the April 2, 2006 election and dissolved the party and banned 111 executive from politics for five years.
The ruling against Thammarak came on the same day as the fiveyear political ban expired.
Following the protests by the yellowshirt supporters, then prime minister Thaksin Shinawatra dissolved the House but the Thai Rak Thai was the only major party contesting the election as opposition parties decided to boycott the poll. Without rivals, the Thai Rak Thai had to win at least 20 per cent of votes in each constituency, which would have been impossible in southern provinces.