Raiders broke in to the firm’s Medway City Estate premises in Strood last weekend and drove one machine worth £20,000 off a cliff edge at the old quarry pit base.
Several items of heavy JCB construction machinery were also left severely damaged.
Police are investigating the incident and H.E. Services chairman Hugh Edeleanu has offered the reward for information leading to the arrest and conviction of those responsible.
Edeleanu said: “The machines that have been stolen are incredibly dangerous, and the perpetrator’s reckless behaviour has risked both their own and other people’s lives.
“We’re carrying out a full investigation and are currently working with the police to find the perpetrators and to bring them to justice.”
Anyone with information should contact Det Con Goddard at Kent Police on 01634 792 467.
