The 54-year-old had earlier pleaded not guilty to three charges over claims she held a PhD from the London School of Economics (LSE) -- credentials she used when applying for New Zealand public service jobs in 1989, 1998 and 2004.
But she later changed her plea to guilty to one charge in a deal which saw the other two dropped.
In Wellington District Court today Judge Bruce Davidson sentenced Thompson to 100 hours community work and fined her $10,000.
The offending came to light after Thompson resigned from her senior position in the Labour Department in 2008 after being accused of a conflict of interest for helping her Kiribati relatives to gain residency in New Zealand.