Teacher accused of having sex with 14-year-old pupil

A teacher at a private Melbourne school has denied having a 12-month sexual relationship with a colleague's 14-year-old daughter, who was also his student, a jury has heard.

The 42-year-old, who cannot be identified due to legal reasons, is accused of having sex with the girl during school hours and at the school multiple times over the course of a year, News Ltd reports.

The man has pleaded not guilty to indecent assault and 16 counts of sexual penetration of a child under the age of 16.

The court heard the pair had sex in a rarely used room at the school, as well as in the teacher's car and at his home nearby.

The girl's mother and the accused worked closely together and were good friends, News Ltd reports.

The relationship allegedly began in 2004, when the teacher was 33.

The teacher's defence lawyer told the jury his client denied the allegations, insisting he had been a 'mentor' to the girl during those years.

"He was a family friend, nothing more," he told the court.

The trial continues.