Farrer Memorial Agricultural High School's Year 12 student-led fundraiser for World's Greatest Shave included Farrer principal Clint Gallagher losing his locks late last week.

Under the bemused eye of the students - and the helpful blast of a garden blower - his hair was shaved after the students reached the mighty sum of $20,000.

The senior students had wanted him to shave along with them back in February, but he essentially ransomed his hair for $6000.

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"Mr Gallagher told them if they could reach a total of $20,000, they could shave him," a spokesperson said.

"[He] thought he was on a pretty safe bet: at that stage the students had only raised slightly over $14,000."

Year 12 kept up the fundraising they'd started about two months ago: running raffles, holding "Banga Sanga" days, selling Zooper Doopers - "anything that would get them closer to the $20,000".

At last report, the students' total was close to $20,170, with more still to come in.