The mandate will be effective from the end of November, the company announced on Thursday.

All SPC casuals, permanent staff and contractors must have at least their first dose of the vaccine scheduled by September 15 and administered by the end of October.

Any site visitors will also be required to be vaccinated.

But the union representing SPC workers says it's "unrealistic" to expect workers to be booked for their first dose in September given many are still not eligible for the jab.

"Taking away a worker's meal ticket because they haven't had the opportunity to be vaccinated fails to recognise some workers will have specific health advice not to be vaccinated," Australian Manufacturing Workers' Union assistant state secretary Victoria Jason Hefford said.

The AMWU said it had not been properly consulted about the plans, despite a legal requirement to do so.

SPC chief executive Robert Giles said workers were being consulted on a "case by case basis" if they were unable to access the vaccine.

Staff are encouraged to talk to their GP or visit local sites like the vaccine hub near SPC's Shepparton factory.

"But we are looking at all options, including a pop-up clinic, to make it as easy as possible for our staff to get vaccinated by the deadline," he said.

Mr Giles said the union's claims about proper consultation were "baseless" as the company had alerted staff and the union on Wednesday "in line with our legal requirements".

SPC chairman Hussein Rifai said the 100-year-old company made the decision to ensure the well-being of workers and the community.

"Lockdowns are not a sustainable solution and the Australian economy needs to open up again," he said in a statement.

"The Delta variant poses a significant threat to our people, our customers and the communities we serve."

All SPC workers will be offered paid time off to get their vaccinations, and two days special paid leave if they become unwell afterwards.

Mr Giles said the company was setting an example for others.

"We firmly believe that it will be manufacturers and innovators like SPC who will help drive Australia's post-COVID economic recovery," he said.

Prime Minister Scott Morrison said he understood some businesses would "have to make choices" about vaccinating their workers.

"Where people are taking decisions that they believe are dealing with their concerns and their interests, then that's something that the Coalition have always been supportive of," he told reporters in Canberra.

SPC, based in Victoria's Goulburn Valley, is Australia's major producer of packaged fruit, and its brands include Ardmona, Goulburn Valley, SPC, ProVital, Kuisine and PomLife.

Australian Associated Press