"I don't like to say it, but they might be Christmas presents."
Two of the bikes, that are all size 20 and red, have already been returned to the school after they were handed in to Whanganui Police.
The school purchased them three years ago at a price of $450 each and they are part of 40 overall that students use every day for both leisure and competition.
Elgar said access was gained to the shed after the padlocks were broken and it appeared the door had been "jemmied" open, possibly with something like a crowbar.
"We've upgraded our padlocks twice now, we've pretty much run out of options on what we can do.
"We talked about cameras, but there's no power over there so that's not going to do it. It is a distance away from neighbours too, at least one and a half rugby paddocks away."
The school is appealing on their Croakee Frog Facebook page and to all in the community to come forward if they have any information about the bikes.