Finance Minister Bill English does not believe the drought will affect the forecast budget surplus in 2014 - 15 but it would affect the economy for a couple of years.
Treasury was looking carefully at the forecasts for the May 16 Budget, he told reporters at Parliament this morning.
"I would expect though, that we will still be able to achieve surplus."
The extent of its effect on the economy was yet to be known but its impact would last at least a couple of years.
It would take some time for farmers that slaughtered stock to rebuild their herds and it would take time to work off the tax losses.