The call is made as the Australian Government gives another $25 million to assist agricultural shows unable to proceed due to the threat of Covid-19.
She understood no A&P show had been open to the public in New Zealand this season.
Some shows had been held, running events such as dog trials and equestrian, but with no spectators.
Those cancelled include Gore, Lake Hayes, Winton, and Wyndham.
The Gore A&P Show committee cancelled what would have been a milestone show next year.
The 140th show was to have been held on February 5.
Show secretary Becs Paterson said the uncertainty created by the current Covid-19 situation had persuaded the committee it was better to cancel now than to axe it at the last minute or hold a show with a reduced programme.
The 140th show was a milestone that needed to be celebrated in style, she said.
"We didn’t want to do a closed-gate show and not involve the public in something that we wanted to make a spectacularly special celebration.
"It would be better to cancel ... and then go ahead in 2023 and do the full show we really want to do."
Shows which have or will run events with no crowd included South Otago, Taieri and West Otago.
Wanaka A&P Show would buck the trend, after it confirmed last week the show would return on March 11-12 to those who are double-vaccinated and hold a vaccine pass.
Ms Walker said Covid-19 had forced show organisers to make hard decisions and societies were "hurting".
The cost of cancelling or having no-one attending was "significant".
Southern Field Days was cancelled about four months out from the three-day event in February next year.
Chairman Warren Ross, of Waimumu, said the organising committee made the decision to cancel before Economic and Regional Development Minister Stuart Nash announced the Events Transition Support Scheme.
Under the scheme, the Government would cover 90% of unrecoverable costs for paid, ticketed events with audiences of more than 5000 vaccinated people, if organisers were forced to cancel or postpone due to Covid-19 public health measures.
Mr Ross said as Southern Field Days attracted more than 10,000 people a day, he expected it would have qualified for the scheme.
After the scheme was announced, the organising committee decided cancelling remained the right decision.
Although the scheme reduced the risk for organisers, it provided no protection for exhibitors.
Exhibitors incurred costs preparing for the show.
Nearly all the exhibitors had supported the decision to cancel, he said.
Another reason for staying with the decision to cancel was because the committee had no idea how they could restrict the crowd to only vaccinated people.
As volunteers checked tickets at the gates, it would be unfair to make them police it, especially when some unvaccinated people "would not make it easy for them".
The scheme was designed to support events which had the highest economic and social impacts in communities.
Professional organised events with large attendances played a big part in how widely the impacts were felt, Mr Nash said,
The high cost of delivering large-scale events meant organisers were also the most likely to cancel if there was no financial support on offer.
Smaller regional events had received backing through the $50 million Regional Events Fund.
The fund was allocated to regional bodies to distribute to events they identified as priorities for their districts.
The Development Clutha group had received $1.5 million from the fund, Mr Nash said.
Another fund, the Domestic Events Fund, gave $10 million direct financial support to small scale events like the Mackenzie Highland A&P Show, the Hawke’s Bay A&P Show, the New Zealand Agricultural Show, and Fieldays.
— Additional reporting Sandy Eggleston and Karen Pasco