The workplace umpire will weigh in on a bitter pay dispute that has cost a supermarket giant tens-of-millions of dollars, as the retailer squares off against its warehouse workers.

The Fair Work Commission will on Friday hear Woolworths’ application to stop United Workers Union members picketing four key distribution centres.

As the industrial action enters its 16th day, thousands of supermarket and bottleshop shelves in Victoria, NSW and the ACT remain empty, costing the company more than $50 million.

The United Workers Union has demanded better pay and changes to a new performance management framework it says puts workers at risk.

Negotiations had stretched for seven months and were ongoing, union secretary Tim Kennedy said.

“The best way to get workers back to work and shelves restocked in time for Christmas is for Woolworths to concentrate on reaching agreement at the bargaining table,” he added.

“Anything else is a distraction.”

Woolworths argues the union’s requested pay rise of 25 per cent over three years would be “materially above inflation” at a time when the chain was “working actively” to keep groceries affordable for customers.

Woolworths did not comment ahead of the commission hearing before Deputy President Gerard Boyce in Melbourne.

Stock shortages include staple products like cereal, toilet paper, meat and dairy goods.

Booze behemoth Dan Murphy’s, which is a customer of Woolworths supply chain provider Primary Connect, has also been affected.

“Endeavour Group is not party to this dispute and we have implemented alternative delivery arrangements to get as much stock to our stores as we can,” a spokesman from Endeavour Group, Dan Murphy’s stock exchange-listed owner, said.

—AAP