More than 500 people attended the meeting at The Woolshed Function Centre on the Southern Field Days site in Waimumu.
The meeting was run by farmer’s group Groundswell.
The group was formed after farmers drove more than 100 tractors through central Gore in October last year to protest against the new National Environmental Standards for Freshwater, introduced a month earlier.
The regulations aim to improve freshwater quality, widen the range of activities requiring resource consents and tighten conditions for many existing consents.
Sheep and beef farmer Logan Evans, of Otamita, said the "unworkable" regulations would stop young people with a dream of owning a farm from entering the rural sector.
He played a recording of the bugle call Last Post as he challenged farmers to take a stand against the "ridiculous new rules".
"Have we got the balls to stick up for ourselves?"
He spoke about the environmental work farmers had been responsible for, such as the Pomahaka Water Care Group.
"You should be bloody proud," he said.
Farmer and environmentalist Jane Smith, of North Otago, said "farmer apathy" was the biggest threat to the industry, so "your voice is so important".
She encouraged farmers to write a list of the environmental work they had completed and share stories about how it had made a difference.
She asked farmers to use science and continue to ask why rather than comply.
She urged every farmer to make a submission "because for every farmer there will be 10 ill-informed muppets who will."
Groundswell spokesman and dairy farmer Bryce McKenzie, of Pomahaka, who drove a tractor in the centre to speak, said a petition seeking a rewrite of the rules had received more than 2500 signatures and been given to the Government.
Speaking to the Otago Daily Times before the meeting, he said catchment groups and regional councils should be setting the regulations.
"There is no one-size-fits-all for the whole of New Zealand."
Future protest action plans were not discussed by the group.