Federated Farmers vice president Chris Lewis claims farmers won't be making much money this year, despite a record forecast milk price.
Ravensdown and Ballance are blaming global supply and pricing dynamics for the latest price rise.
Both have bumped up urea prices by nearly 25% to $1,190/tonne.
Potash prices have also jumped by nearly $100/tonne. Ravensdown is selling potash at $995/t, Ballance at $1000/t.
Ravensdown has raised its superphosphate price from $339 to $367 but have told farmers that the new price will be maintained for the next six months.