Perth Royal Show punters were outraged after a major EFTPOS outage blamed on Telstra impacted the festival's biggest day. 

Organisers said large crowds added to the disruption, with long queues at many of the ATMs working across the venue.

Royal Agricultural Society CEO Robyn Sermon said the outage was a Telstra issue and she was seeking clarity if it was fixed in time for show goers today.

"Many of the ATMs did get back online last night ... it was a particularly large day yesterday too," she told 6PR Breakfast hosts Oly Peterson and Jenna Clarke.

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