The price of superphosphate is likely to increase to $700 a tonne according to Ballance Agrinutrients chair David Graham.
That would be a 218% increase in 18 months and a 49% rise since June.
A year ago, superphosphate was selling for about $220 a tonne, but Mr Graham said $700 a tonne was not unrealistic given soaring international prices.
Fertiliser is the biggest item on most farm budgets. The price is already putting a dent in the high dairy payout, it will be even worse for sheep and beef farmers even with the improved prices.
And those who think a drop in the value of the dollar is good for primary producers might want to consider the impact on the price of fertiliser.