She was employed at the school for about 12 years before her resignation last year.
While working at the school, she had formed sexual relationships with “a number of students”, who tended to be from more vulnerable families, and were usually involved in sport, a police summary of facts said.
However only two students were under the legal age of consent, which formed the basis for the charges laid.
She had already been automatically added to the sex offenders’ register.
Cooney’s husband Paul is a constable in Blenheim. His posting to Marlborough was his first job as a police officer; previously he worked as a teacher at Hillmorton in Christchurch.