Agencies are facing a major problem because there isn't enough transport to get the grain, straw and silage to where it is needed.
Grain and feed agents across Canterbury say since the official declaration of a state of drought in many parts of the North Island last week, the number of inquiries has shot through the roof.
While there is plenty of surplus feed in Canterbury to sell, there are not enough heavy trucks available.
Federated Farmers grain and seed vice-chairman David Clark said there is talk of backlogs of at least six weeks to get feed to the North Island by truck.
However, Road Transport Forum chief executive Ken Shirley says there is no lack of capacity.
Federated Farmers representatives are meeting this week with transport providers to look at various options that could include trains and ships.
The effect of the drought is also hitting business confidence in the agricultural sector .
A BNZ Confidence Survey has found participants expect poor prospects in the next six months, and the drought is having, and will continue to have, a major negative effect on farm sales and real estate.
It also shows dairy production in the South Island is holding firm and grain and seed growers in Canterbury report excellent harvesting conditions that have resulted in high yields and quality.
But prices are below the level needed to ensure further investment in plant and machinery and the repayment of debt.
The survey shows the dry conditions are now concerning South Island farmers.
Livestock sent south
The transport industry says it is moving tens of thousands of livestock to the South Island to escape drought-stricken farms in the North Island.
KiwiRail says it transported 75,000 sheep across Cook Strait in February, 47% more than the same period last year.
Road Transport Forum chief executive Ken Shirley says it has noticed a similar increase, which has provided a boost in income for truckers.
"The returns on capital for stock transport has not been good for a long time but when you're moving large volumes it certainly means utilising trucks."
Mr Shirley says there is no lack of capacity to move stock and feed between islands in response to the drought.
Fonterra has put its tanker fleet on standby to deliver water to parched rural communities if needed.