Gateshead haulage company have had fuel stolen five times in the past six weeks.
Fuel raiders siphoned off diesel from HGV tanks after breaking into Tony Carter Transport in Dunston causing hundreds of pounds in damages and losses.
Northumbria Police said there has been a spate of diesel thefts in the waterfront area and an investigation is under way after CCTV caught the thieves entering the truck compound on numerous occasions.
The firm have spent thousands of pounds installing a CCTV system but said it has not deterred the thieves.
Northumbria Police haves asked for anyone with possible information should contact the police.
