Pedigree and Whiskas items made by Mars Petcare have largely vanished from the two major grocery chains over the past week. 

Coles and Woolworths stores in Bendigo have put up notices about the shortages on empty shelves where the products would normally sit. 

National Union of Workers regional organiser Mark Schmidt, who represents workers at Mars' Wodonga factory, made the comment on Wednesday.

"Mars has had a price rise with its product and Woolworths and Coles are trying to get in and get their cut and my understanding is that's why there has been a hold-off," Mr Schmidt said.

"The warehouses are full, so it's not that there's a shortage in the product. It's the fun and games that go with a product price rise."

At Woolworths in Kennington, a customer notice on an empty shelf said there has been supply shortages on some brands of pet food.

A notice at Coles in Bendigo says Whiskas, Pedigree, My Dog and Dine products were temporarily unavailable.Notices attached to Coles shelves at outlets stated: "We regret to advice that due to unforeseen circumstances some of our Whiskas, Pedigree, My Dog and Dine pet food products may be temporarily unavailable. "We apologise for any inconvenience caused."

However, the IGA in Strath Village appears to have had no issues with its flow of dog and cat food from Mars.

Mr Schmidt said that he expected Pedigree and Whiskas goods would return sooner to Coles than Woolworths stores.

Hours later in an email responding to inquires a Coles spokeswoman announced that there had been progress.

"Following a short-term availability issue, Mars Petcare products will start returning to Coles shelves this week," she said.

A Woolworths spokesman would not say if pricing was the issue and when the pet food would refill shelves.

"It's not our practice to make public comment on our commercial arrangements with suppliers," he said.

"As stated yesterday, we're working with the supplier to improve availability for our customers as quickly as possible."

Mars Petcare Australia corporate communications manager Andrea Bradley was asked on Tuesday and Wednesday about whether a dispute was behind the shortage. She declined to say if that was the case, saying on Wednesday "at the moment it's a supply issue".

Mr Schmidt said that the lack of deliveries to Woolworths and Coles had not affected workers' service - "there's been no loss of hours due to it".

​ Mars Petcare halted production earlier this month and in February because high electricity costs meant it was not viable to continue can and single serve output.

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