Judge Susan Cohen described Dennis' offending as ''serious'' and a ''betrayal of trust''.

Michelle Lynn Dennis, 33, had sex with the boys, aged 14 and 17, while employed as a music teacher at Ballarat High School.

The County Court at Ballarat heard Dennis sent more than 1300 text messages to the students over a two-year period.

She also sent one of the boys naked pictures of herself and invited one of his friend's to have a threesome with them, which the friend rejected.

Dennis pleaded guilty to two counts of sexual penetration of a child under supervision and one count of sexual penetration of a child under 16.

She was convicted and sentenced to four years and three months' jail, with a minimum of two years and 10 months to serve.

She was also ordered to be placed on the sex offenders' register for life.

Judge Susan Cohen described Dennis' offending as ''serious'' and a ''betrayal of trust''.

''Teachers have a high ability to influence students and that gives them a responsibility not to abuse their position,'' she said.

Judge Cohen said Dennis had initiated the sexual liaisons and shown ''little remorse'' for her actions.

''Each occasion was instigated by you where you drove them somewhere inappropriate,'' she said.

Dennis sat in the dock with her head down during the hearing and cried when her sentence was read out to the court.