Twenty-three farms throughout the country will open their gates. In Otago, the 56ha AgResearch Invermay Waiora Farm on Silverstream Valley Rd, at North Taieri, and the historic Totara Estate, south of Oamaru, will be on display.
The North Otago Farm Day is being held as part of the Harvest Home Festival.
Otago Federated Farmers president Mike Lord said Farm Day aimed to promote New Zealand's agricultural sector, and this year it was focusing on the sector's environmental impact.
Mr Lord said for AgResearch, sustainably farming Waiora meant managing it to ensure the environment was protected, animals were healthy and the business successful.
The federation's national president, Don Nicolson, said the sector was under public scrutiny about its environmental impact, and he urged the public to talk to practising farmers who will attend the farm days about what they did.
"It's about us going on the front foot. Our dairy farmers are open to talking about how they manage and recycle effluent in ways that would put many of our towns and cities to shame," he said.
The farms will be open from 10am to 3pm. Entry to Waiora will be free, but there will be an admission fee to the Totara Estate, as part of the Harvest Home Festival.