FedEx couriers are threatening to walk off the job on one of the busiest online sales days of the year, as their union writes to Amazon and Apple about an increasingly bitter wage dispute.
The Transport Workers' Union claims FedEx is refusing to come back to the table and bargain after days of strike action, with workers considering further rolling stoppages across Australia on Black Friday.
The parties have been in dispute over pay and conditions for months with a string of strikes this year, as negotiations over a new enterprise agreement continue to stall.
Earlier this week, about 2000 FedEx workers in New South Wales, Victoria, Western Australia and Tasmania walked out in four-hour stoppages.
The TWU has claimed workers who took part in the strike action were locked out by FedEx for the remainder of their shift and the following full shift, meaning many they will lose two days' pay per action.
"FedEx has refused to come back to the table, leaving workers no choice but to consider further rolling stoppages across the country which could begin as early as tomorrow," the union said.
"Following FedEx's lockout retaliation, workers are no longer required to provide three days' notice ahead of industrial action."
The union has sent a letter to FedEx's major retailers - Amazon, Apple, Sony, JB Hi-Fi, Harvey Norman and Wesfarmers - asking them to urge FedEx to settle the agreement.
The TWU is disputing FedEx claims it has offered workers "an industry-leading three-year agreement".
"FedEx's offer is in fact spread over four years and fails to provide wage rises to keep up with the cost of living," TWU national secretary Michael Kaine said in the letter.
"FedEx's heavy-handed retaliation to lock workers out for two full days caused self-inflicted injury to the business and imposed extensive, unnecessary disruption for clients during the busiest period of the year in the lead up to Black Friday.
"Workers want this resolved as quickly as possible so that they can get on with the important job of delivering for Christmas."
The union is calling for FedEx to guarantee workers that their pay will meet CPI and to settle job security issues around contractor rates of pay.
AAP has contacted FedEx for a response.