A glitch with an online platform used for mart sales was resolved today after many sales were cancelled and animals were returned to farms unsold.
The IT system failure crashed the online bidding platform operated by one company at 17 sales, for several hours, today.
All mart sales are now held online due to Level 5 restrictions, meaning people bid for animals that they view on video streamed from marts.
One of the biggest online platforms, LSL - Livestock Live - experienced problems and the platform was down for much of the day.
A spokesperson told RTÉ News that they had a "server issue". But hundreds of animals were left waiting in holding pens for sales to take place before returning to farms unsold.
The Irish Farmers Association said the Government needs to review the Level 5 operating procedures in marts "as a matter of urgency".
IFA President Tim Cullinan said: "Relying on the 'online only' system is too ambitious. The system has been bedding down well as a complementary system to bidding at the ringside.
"However, clear challenges have now emerged related to broadband and the ability of systems to cope with the volume of cattle and bids during what is a hectic time of the year," said Mr Cullinan.
He said that the Department of Agriculture needs to address the issues which have emerged.
"Everybody is doing their best, but the protocols need to be reviewed to allow a limited number of buyers around the ring, we need to allow some level of in-person trading once social distancing and other guidelines are fully and rigorously followed," he said.
The Department of Agriculture said marts affected by difficulties holding online auctions may need to invoke contingency measures.
A statement from the Department said in the event of similar difficulties in the future, marts may need to put in place, "contingency measures for extended retention of animals at the facilities or that animals may need to be returned to their herds of origin, to best support the welfare of the animals".
But it has indicated there will be no change to existing protocols which prevent buyers and sellers being physically at sales.
The statement said: "It is important to ensure that the necessary public health guidelines are followed."
ICOS, which represents many marts, said the difficulties highlighted the problem with online-only sales.
"This is an exceptional situation," said Ray Doyle from ICOS.
"We cannot leave hundred of animals waiting to be sold for hours on end. Some contingency must be agreed when IT problems stall sales."
This is a very busy time of year with many farmers selling weanlings.
RTÉ News spoke to numerous marts where sales were stalled today.
The Mart Managers Association of Ireland said the problem was presenting animal welfare issues and needs to be resolved immediately.
Several online platforms are used by marts and LSL is among the most popular.
MartEye and MartBids, two of the other popular platforms, were not experiencing any problems and sales continued as normal.