An estimated 20 per cent of the cereal crop in counties Louth, Dublin and Meath has yet to be harvested as millers and compounders strive to cope with a record harvest.
Irish cereal yields, now the highest in the world, were expected to deliver around 2 million tonnes of grain this year but the latest estimates show the national crop rising to over 2.2 million tonnes.
The record harvest follows a combination of suitable weather and the use of new fungicides which protect cereal crops better, according to Teagasc's chief tillage adviser, Mr Paddy Browne.
"Our wetter climate is better than those of our competitors for growth but our weather is ideal for the spread of diseases which keep down yields.
"These new fungicides, which are naturally occurring, have now meant that our 15,866 growers are getting average yields of around three tonnes per acre on spring barley and close on four tonnes on winter wheat."
However, he said, crops treated with the fungicides tended not to ripen early and were harvested much later in the year.
"In the north-east this year, we estimate that nearly 20 per cent of the winter wheat crop has yet to be harvested and the weather is getting very difficult now. Crops may sprout again or lodge - fall down because of rain or wind," he said.
He said the trade was facing difficulties coping with the size of the crop and many millers and compounders were being forced to rent additional storage space.
The two largest groups involved in buying grain from farmers, Glanbia and Drummonds, said yesterday they both had to find extra storage.
A Glanbia spokesman said its 41 intake points and 16 drying units were working flat out to cope. "We not only accept the grain at our intake points but then it has to be moved to the drying units and that is where the back-up can take place.
"The size of the harvest created a logistical problem for us but we are managing and we have rented additional space over and above what we normally take.
"The harvest is complete in much of the south of the country but there is still more to come in the north-east, where harvesting is now becoming difficult."
The Drummonds spokesman said it was also under tremendous pressure this year and had to find additional space.
"We estimate that about 20 per cent of the crop in counties Dublin, Louth and Meath has still to be harvested and we know a number of farmers with over 200 acres of crops which are still in the fields.
"It will probably be Tuesday now before harvesting can begin again because of the bad weather so I am afraid while yields were high, this bad spell will take some of the shine off the harvest for some of the growers."
This year 15,866 Irish farmers indicated to the Department of Agriculture that they were going to grow grain on an estimated 700,000 acres.
It is estimated they grew 180,000 acres of winter wheat and spring wheat and barley made up the rest of the national crop.