At the Gore District Council's meeting on Tuesday, councillors voiced concerns about the issue after it was revealed the bill for repairing damage to bridges was close to $50,000 over the past 12 months.
Gore district roading manager Murray Hasler said if those responsible for the damage could be identified they would be made to "foot the bill".
However, no-one had owned up to causing the damage, so repairs had to be funded from rural rates, he said.
All the bridges affected were single-laned and met legal width requirements. However, in some instances, it was obvious by the marks and gouges left behind that the machinery had been too wide for the bridge.
Mr Hasler said the damage caused was not only hitting the ratepayers' pockets, but was also jeopardising the future of those bridges where traffic volumes were low but maintenance costs were high.
If the New Zealand Transport Agency, which subsidised maintenance work, decided the cost-benefit ratio was unacceptable, the council would have to consider the viability of retaining the bridges.
The council urged contractors to consider their routes and the width of their equipment, particularly when purchasing new machinery. Farmers should only engage contractors whose equipment would not damage bridges they relied on to access their properties, he said.
Clutha District Council district assets manager Jules Witt said damage to bridges in his area was also frustrating.
"It's about the same as it always is. We do get this issue off and on, but there has been no jump in the number of bridges damaged."
Mr Witt said the council's bill for fixing rural bridges was similar to the Gore district's $50,000, but covered a roading network about three times the size of the Gore district's.