The rising cost of aviation fuel is forcing topdressers to increase charges to farmers by up to 8% for their aerial spraying services.
In the past month, aviation fuel prices have risen by more than 25 cents a litre
The Agricultural Aviation Association says aerial operators have no choice but to pass on that increase, though executive officer John Maber says they're often reluctant to do so because of loyalty to their farmer clients.
Mr Maber says increases will range between 2.5% and 8%.
He says aerial operators are also struggling to meet a spike in demand for their services, due to a lift in farmer incomes which means increased fertiliser use.
He says the agricultural aviation industry cannot suddenly increase capacity to match the rise in demand.