Food prices look likely to rise again after one of the country's largest fertiliser co-operatives, Ravensdown, announced its third price rise in ten months while warning further price increases were inevitable.
The other co-operative, Ballance Agri-nutrients, has a policy of reviewing pricing each quarter and last increased its prices in June.
It plans to announce a likely price increase next Monday.
Ravensdown announced yesterday that superphosphate, the most widely used fertiliser, was now worth $560 a tonne, more than double its price last December, while high analysis products urea and DAP have respectively risen 180% to $1111 a tonne and 90% to $1783 a tonne.
In December, superphosphate was worth $264 a tonne and there is speculation it could hit $700 a tonne.
Ravensdown chief executive Rodney Green has laid part of the blame for the price rises at the door of Ballance, saying with quarterly pricing, it was obvious to their shareholders that the price was about to rise so they started stockpiling fertiliser meaning some Ballance stores ran out.
This caused a run on Ravensdown stores, said Mr Green, which had put pressure on their stocks.
Trucks have been queuing at some stores ahead of the price rise.
A Ballance spokesman rejected that claim, saying the only supply hiccup was a mechanical fault delaying a a shipment of urea to the South Island.
Yesterday's Ravensdown announcement was likely to prompt a run on stock ahead of Monday's price review by Ballance.
Ballance has kept its superphosphate price at $460 a tonne, urea at $921 and DAP at $1412, but the spokesman said it faced the same international pricing issues as Ravensdown.
It is the busiest time of year for farmers applying fertiliser, so the price increase comes at a difficult time.
Meat and Wool New Zealand's economic service executive director Rob Davison said worldwide demand for fertiliser was pushing up raw material costs and it would inevitably feed in to higher global food prices.
He was forecasting a 25% drop in the volume of fertiliser applied on New Zealand sheep and beef farmers in the coming year.
Farmers would have budgeted a set amount for fertiliser in the coming year and would stick to that, but the volume used would be well down and strategically applied.
Mr Davison said farmers were also making greater use of lime, which chemically released phosphate stored in the soil, while urea and DAP would be beyond the budgets of most sheep and beef farmers.
Ravensdown chairman Bill McLeod said in a statement that the country was yet to see the full impact of what he called "the phenomenal increases in demand for raw materials".
China was still to decide if a tax on fertiliser exports would remain while India has started aggressively competing for fertiliser raw materials.
