Managing director Philip Nieman said there were high defects in the potato crops, including, hollow heart, malformation, high sugars and size problems.
"The crop was further compromised by a black frost in mid- June, and again in mid-July, which will result in prolonged problems with potatoes that are not fully matured, through to the end of November."
Nieman said the result was a severe shortage of fresh potatoes that met the company's specifications for processing.
"At the same time, as a result of the drastic shortage in supply, it is expected that the price of fresh potatoes will increase dramatically in the short term."
Nieman said McCain had taken "every possible measure" to minimise short supply to customers and consumers while at the same time ensuring that it maintained quality standards.