Mr Wiedemann said access to machine parts and abattoirs would be the two most immediate negative impacts for Wimmera farmers in the absence of workable solutions

However, he said he was confident these could be achieved.

While regional Victoria returned to stage three restrictions on Wednesday, Melbourne has entered stage four. This means people can only travel five kilometres from their home and many businesses must close or operate at a reduced capacity, among other measures.

"We've got two of the major Australia-wide distribution centres (for parts) in Melbourne - including John Deere - so we've been fielding calls form farmers around parts availability," Mr Wiedemann said.

"It will be devastating... if you have a machinery breakdown during harvest there will be a lot of pressure put on businesses associated with those machines at the time. We want to avoid any potential conflict in parts availability between the businesses, so we have to start thinking now about how that might work and make sure supply chains are open."

Mr Wiedemann said he expected to find out more from the state government on this matter on Thursday.

"I think everybody realises we are in unchartered waters, it's a just a matter of putting the common sense principle across what needs to happen to keep industries going," he said. "We are spending hours a day every day on the phone working on issues cross-border."

Western Victorian MP Emma Kealy has called for exemptions for small regional abattoirs, which are the only regional businesses subject to the same stage four level of restrictions as Melbourne. Member for Ripon Louise Staley has offered support to workers affected by the changes.

Mr Wiedemann said Ms Kealy's suggestion was "common sense".

"in Australia, 60 per cent of grain farmers run livestock too, and in the Wimmera it's a higher percentage," he said. "It is very important that farmers looking at livestock have confidence around what is going to happen in the market."

Mr Wiedemann said the availability of staff for farmers during harvest, when many in the Wimmera rely on seasonal workers, was a longer-term issue related to the pandemic. He said GPA was working to see if retrenched airline workers could fill these positions.

Victorian Farmers Federation president David Jochinke, of Murra Warra, has also been in talks with the state government. He said farmers were concerned about restrictions to their business and business interruption, labour shortages, freight and logistics problems along with issues around access to inputs.

"We understand the trust that has been placed in our sector and that we are accountable for keeping Victorians fed during this state of disaster."

"The VFF today wrote to our members to reinforce the importance of implementing COVID-19 action plans, which are critical to keeping the agriculture supply chain open."

"Our clear guidance to farmers is to be extra vigilant as COVID-19 reaches our doorstep. We must implement the best protective measures for our businesses and our workers: face coverings or visors for employees, ceasing communal gatherings, installing screens/curtains, furloughing of staff, physical distancing, cleaning and disinfection measures and insisting on personal hygiene and use of sanitisers, minimizing the number of people coming onto your farm."