Woolworths Group said its Australian food sales have been negatively affected by about $50 million due to industrial action, as workers seek pay rise in excess of 25 per cent over three years.

“Until the industrial action is resolved, a further impact to sales is expected,” the supermarket chain said in a statement. “The full financial impact at this stage is unknown.”

The United Workers Union (UWU) launched an indefinite strike action at four Woolworths sites on November 21, causing stock flow limitations across some product lines in some of the stores in Victoria, southern NSW, and ACT.

Moreover, Woolworths said that it has failed to reopen its Melbourne South Regional distribution centre as striking workers refuse to give guarantee of safe passage to other staff who wish to work.

The company said that its latest offers would take hourly rates at the affected sites to about 40 per cent above the award, to address the strike, which has now extended to 12 days.

“We are working hard to try and improve the situation and would like to thank our customers for their understanding and for treating our teams with respect,” said Woolworths CEO Amanda Bardwell.

In a statement, the UWU said that Woolworths must prioritise its workers’ well-being or else continue to suffer from empty supermarket shelves in the lead-up to Christmas.

“Workers have reported feeling pressured to cut corners and work unsafely or lose their job if they don’t pick at higher speeds,” said Tim Kennedy, UWU national secretary.

“Woolworths workers are striking for a cost-of-living wage increase and to be paid the same rate of pay for doing the same work under a national agreement.”