The United Dairyfarmers of Victoria annual conference has been cancelled, due to the latest coronavirus lockdown.
The event, which was due to be held on July 23 in Melbourne, had already been rescheduled.
The UDV will not carry over registrations.
President Paul Mumford said the decision was "so disappointing.
"We had no option, health is paramount and we couldn't put our members in a compromising position," Mr Mumford said.
"It's disappointing we weren't able to bring our members together, to not only celebrate our industry, but to engage in open debate about resolutions and the the future direction of dairy in Victoria."
It will contact branches that submitted resolutions and give them the opportunity to send them directly to the policy council, for decision, withdrawal or holding over until next year.
Those outcomes will then be communicated to the UDV membership.
"We didn't want to put a stop to everything and wanted our members to have flexibility, in how those resolutions were addressed," he said.
"If they still want a resolution, brought to the membership for discussion, we can do that next year."
He praised UDV staff for the work they had done in organising, and having to postpone and then cancel the conference.
"Our office has done a huge amount of work, not just for the first conference, but the second and the third," Mr Mumford said.
The cancellation follows that of the Australian Sheep & Wool Show, which was to have been held in Bendigo, this weekend.