The distinctive Mongoose Supergoose BMX bike, valued at $2500, was stolen from a shed on his Ortive St property at the end of January.
The bike was bought in Australia "and I'm pretty sure it's the only one like it in this country," McElhinney said.
It was a present from his parents before he attended the BMX World Championships in Adelaide in 2009.
"It was gutting to wake up and discover the bike gone [at the end of January] and I've had to use an old bike to compete on since then, so it's very annoying, as well as gutting."
He has been racing BMX for more than 20 years and plans to compete in the South Island championships at the end of this month and then the nationals in Rotorua at Easter.
Senior Constable John Chambers, of Cromwell, said a reward was being offered for the return of the bike and people could provide information anonymously by phoning the Crimestoppers number.
"Other bikes in the shed were ignored, so it's obvious this one was targeted, and it could've been stolen to order," he said.
"Maybe someone out there has seen it - it's a pretty distinctive bike- or has heard about it on the grapevine, so we're appealing to the public to help us."
