Brazilian cattle farmers are making the most of the unusually wet weather to hold on to and fatten the animals.
A frigorifico owner told The Grocer: "Lack of cattle has pushed prices to levels we can no longer afford to pay."
The unseasonal weather has added to their currency problems as the Real has been revalued by 10% against the US dollar since the start of the year.
Corned beef prices have already risen by a dollar a case and, according to UK importers, are likely to go even higher.
UK selling prices have remained unchanged due to the strengthening of sterling, but if f.o.b. levels go higher, retailers will be faced with increased costs for the second half of the year.

n egg brain power
A range of eggs that help boost the brain has been launched into Waitrose next week.
Intelligent Eating Eggs, from Stonegate Farms, are enriched with Omega-3 and DHA long chain fatty acids, which is vital for the health and development of the brain.
Stonegate Farms said the eggs, which provide an alternative to oily fish thanks to their acid content, are not genetically modified.
A small amount of refined tuna oil is included in the diet of the hen.
Richard Langdon, from Stonegate, said: "Very few people have adequate levels of DHA in their daily diet, which is why we've developed Intelligent Eating Eggs."
n deliveries up 8%
Daily milk deliveries during April soared by a massive 8.4% compared with those recorded during March, according to the Rural Payments Agency.
This brought total monthly supplies to the same level as the record level reached in April last year.
On that occasion, the processing industry was unprepared for the spring surge in output, and milk had to be exported to Ireland and the Continent to avoid any wastage.
This year, those problems were avoided due to the availability of additional UK processing capacity to make butter and skim milk powder.
While volumes may have been high, there was a fall in butterfat or cream content from 3.99% last year to only 3.9% this year.
This means processors will need more milk to produce the same volume of butter or cheese.

n NFu price call
Farming leaders are calling for an increase in the milk price.
The National Farmers' Union said the weakening of the pound and the increase in the Intervention Milk Price Equivalent to 19.5p a litre must generate a price rise for UK dairy producers.
NFU milk chairman Terrig Morgan said that because the IMPE is a support mechanism, he expected it to be the minimum price delivered to producers.
The NFU has been pushing for the EU target price to be the benchmark for UK producers and the weakening of sterling has pushed the price up to 22.5p a litre.
Morgan said: "The situation is clear.
"Dairy farmers rightly expect and demand that milk prices must rise."