South Island cattle breeders have had to withdraw their entries from this week's New Zealand Dairy Event, because of fears it could spread the cattle disease Mycoplasma bovis.
Breeders from around the country show their premier stock to international judges at the two and a half day event, which starts in Feilding on Wednesday.
The event's deputy chair, Johanna Wood, said about 350 cattle were entered in the competition - but 27 of those from the South Island were asked to withdraw last week.
She said that was upsetting for everyone.
"They're disappointed - we're disappointed - because we know that there is some jolly good cattle down there...
"There's a huge amount of preparation that goes into it beforehand."
That decision followed the discovery of Mycoplasma bovis on four more farms earlier this month - bringing the total number of infected properties to 18.
The biggest cluster of infected farmers are in the Canterbury and Southland regions.
The Ministry for Primary Industires and NZ Dairy had advised against the co-mingling of cattle between islands, she said.
MPI staff would be attending the show to offer advice to farmers on how to protect their farms from Mycoplasma bovis.
The New Zealand Diary Event would go ahead for North Island exhibitors and updates would continue to be provided to exhibitors, she said.