The Public Service Association wants psychometric testing in the workplace stopped, saying it is being used to determine whether people keep their jobs or not.
It says figures it obtained under the Official Information Act show Government departments spent $1.5 million on the testing last year.
The biggest spenders were the Department of Corrections at $376,439 followed by the Ministry of Education at $198,823.
Tests include true and false answers to various questions including, "I set high standards for myself", "I often lose my temper" and "I am not very inventive".
The PSA says staff may have worked in an organisation for years and their skills, aptitudes and failings should be well known to employers.
The union has written to the State Services Commissioner asking that psychometric tests not be used in business restructuring, especially where redundancy is a possible outcome.