More than 150 milk tank drivers kicked off what is set to be an unprecedented three days of strikes in the Victorian dairy industry that could force farmers to pour milk down the drains.

Transport Workers Union members at dairy giant Saputo started 48 hours of stoppages and work bans at 3am on Tuesday, ahead of another 48-hour strike by 1400 dairy production workers at Saputo, Fonterra, Peters and Lactalis set to start on Wednesday.

The strikes, which come as farmers are at the peak of the spring milk season, will amount to the largest in the industry in living memory and aim to pressure dairy companies to lift pay to keep up with cost of living and guarantee job security.

Saputo is the country’s largest dairy processor and owns or services major household brands, such as Cheer, Cracker Barrel, Devondale, King Island Dairy, Liddells, Mersey Valley, Southcape, Tasmanian Heritage and Warrnambool Cheese & Butter.

TWU Victorian assistant secretary Mem Suleyman said members, about 80 per cent of the Saputo driver workforce, had decided to strike after eight months of failed negotiations around cost-of-living wage rises, job security and leave entitlements.

“Saputo needs to bin this industrial war they’ve started, and they need to give the respect to these regional families that they deserve,” he told The Australian Financial Review.

The union and Saputo were locked in negotiations on the first day of the strike, although sources said talks were unlikely to result in cancellation of industrial action.

Saputo operations director Gerard Lourey said the company was committed to resolving the negotiations “amicably and swiftly” and had put contingency measures to minimise disruptions.

United Workers Union national secretary Tim Kennedy, representing the 1400 dairy processing workers set to strike at 13 dairy plants on Wednesday, has told ABC that “this is the biggest dairy action in living memory, it’s never happened on this scale”.

“They’re not even asking for a wage increase that matches inflation, just 5 per cent or so that gets them a little closer to being able to keep up with skyrocketing costs,” he said.

The Consumer Price Index is currently at 6 per cent in the 12 months to the June quarter and the union says workers have taken real wage cuts while companies post record profits.

While Woolworths’ milk supplies will not be affected by the Saputo action, its branded milk in Victoria comes from Fonterra’s plant.

A Woolworths spokesman said that “we’re in close contact with our Victorian milk supplier, and we’re working on contingency plans to minimise any potential disruption to our customers”.

Coles, which this year purchased two milk processing facilities from Saputo to shore up its branded milk supply, did not respond to requests for comment before publication.

Fonterra Australia supply chain and operations director Rob Howell said the company had offered workers an increase of at least 10.5 per cent over three years, with more leave options.

He said he believed there would be minimal disruptions from the strikes.

“Our farmers will continue milking, and we will be doing everything we can to ensure that their precious, perishable milk can be collected and not wasted,” he said in a statement.

Lactalis said in a statement that it “will do everything within our power to ensure action by the UWU and the Australian Manufacturing Workers’ Union does not result in farmers having to dump milk”.