A 14 tonne excavator and a six tonne swivel skip dumper were burnt out in the attack on a road works job during the first weekend of this month.
PC Ady Harvey from Tandridge Area Patrol Team said: “This was a shocking attack which has caused thousands of pounds worth of damage.
“The owner of the business is understandably distressed by this incident and we are determined to trace those responsible and bring them to justice.
“I am urging anybody who witnessed any suspicious activity in the area around the time of the incident or with any information to contact us immediately.”
Surrey Police urges anybody with any information to call 101 quoting reference number, 45160056901