Nine former Atlanta teachers have been jailed for between one and seven years for conspiring to cheat on standardised tests in one of the largest-ever scandals of its kind in the US.

The offences, which date back as far as 2005, were described by Fulton County Judge Jerry Baxter as "the sickest thing that's ever happened in this town" as he passed down the sentences, according to NBC News.

A total of 10 former Atlanta state school teachers were convicted in the scandal, although two of them, Donald Bullock and Pamela Cleveland, struck plea bargains.

Bullock, a former testing coordinator, was sentenced to six months of weekends in jail, while former teacher Cleveland received one year of home confinement, plus five years' probation.

The seven-year sentences were conferred upon former administrators Sharon Davis-Williams and Tamara Cotman, and former schools executive Michael Pitts.

The teachers were found guilty of cheating on standardised tests since 2005 in a bid to meet federal and local testing standards. They had hoped the improvement in students' results would impress the supervisors and in turn help them secure performance bonuses or preserve their jobs.

The teachers claimed they were driven to conspire after feeling pressured from former Superintendent Beverly Hall, who passed away in March after suffering from breast cancer.

Atlanta cheating scandal
Fulton County Superior Court Judge Jerry Baxter describes his feelings when sentencing the Atlanta Public school educators for racketeering charges in one of the largest US test-cheating scandals in Atlanta, Georgia on April 14, 2015. Reuters