Some people just want to paint the world grey.

A 45-metre, publicly-funded mural, which a team of high school students had worked on for eight weeks, has been painted over just hours after it was finally finished.

Coburg High School students Victoria Clavero, Georgia Clarke and Caroline De Nato with the dachshund they painted over the defaced mural on Thursday morning. Credit:Simon O'Dwyer

The Coburg Senior High School art students had been commissioned by VicRoads to liven up a wall beneath the Bell Street overpass but their rainbow mural has already been covered over with dull grey paint.

Coburg High School art teacher Theodore Hartman helped oversee the painting of the mural and said it was a Year 10 class project that had been mostly organised and designed by students.