A Melbourne private school teacher who told a 17-year-old schoolgirl he was "feeling horny" and wanted to sleep with her has been suspended for just six months.

Yukihiro Nagashima, a former teacher at Beaconhills College in Pakenham, confessed to sending inappropriate Facebook messages to a student at a Japanese sister school in September 2015.

The teacher has been suspended for six months. Credit:Eamon Gallagher

He was also accused of asking the student to send a photo of herself masturbating – an allegation he denied but one which was substantiated by the Victorian Institute of Teaching.

In a decision published this week, the teaching watchdog said Mr Nagashima, "on his own admission, compromised and violated his professional relationship with the student".