The Royal Agricultural Society of NSW president Robert Ryan on Friday afternoon said the Sydney Royal Show has been cancelled.
"It is distressing and disappointing to cancel the show," he said, adding it was to protect people's health.
"There are many people who will be very upset by this decision, and this is the first time the Sydney Royal Easter Show has been cancelled because of a public health emergency since the Spanish Flu pandemic in 1919," Mr Ryan said.
RAS chief executive Brock Gilmour said the decision was a huge disappointment for the show community, particularly exhibitors and visitors from rural and regional NSW.
"The Sydney Royal Easter Show generates $250 million in economic activity each year and the decision to cancel will affect many stakeholders and businesses, including the RAS," Mr Gilmour said.
"We are in the process of implementing a number of measures to deal with priority concerns including refunding or holding over competition fees, refunding tickets purchased by the general public and unwinding contracts with hundreds of suppliers.
"This process will take weeks and we will work hard to keep our stakeholders informed as we work through the detail," he said.
"Cancelling the show will cost the RAS tens of millions of dollars, and as a not-for-profit association, we will be working with the NSW government to soften the financial hit to the RAS and to our stakeholders."
NSW Farmers' president James Jackson said it was a necessary and disappointing outcome of the coronavirus outbreak.
"It is the right decision," Mr Jackson said.
"Stemming the outbreak must be priority, but the Easter Show is an important event for our sector.
"It helps promote local food and fibre production and it is an important social and networking event for many farmers.
"Like many sectors, this virus will be a serious impost on agriculture."