Toll Holdings faces strike action by more than half its workforce after staff voted overwhelmingly in favour of protected industrial action due to a lack of progress over a new enterprise agreement.
Talks between the Transport Workers Union and Toll became bogged down in July over matters including job security, superannuation payments and outsourcing of work.
It led to the union applying to the industrial umpire to carry out a ballot of members who worked at Australia's largest listed transport company.
The results of that ballot, released on Tuesday, show about 85 per cent of the 2920 votes received were in favour of protected industrial action. It can include work stoppages of between one and 72 hours.
The possibility of workers exercising their right to take industrial action threatens to disrupt the supply chains of retailers throughout the country. Toll transports goods for retailers including Coles and Woolworths.
The enterprise agreement covers about 10,000 workers at Toll - about 8000 of whom are TWU members.
TWU national secretary Tony Sheldon said the vote sent a clear signal that Toll workers would not agree to a second-rate deal. "It's always been our intention to reach an agreement with the company that our members can vote on, but after more than 100 hours of negotiations we still remain some distance apart," he said.
The main sticking point has been whether Toll will allow the enterprise agreement to be extended to new work, especially in warehousing. The union argues that the company has created new business units that pay lower rates.
Despite the threat of strike action, negotiations between the company and the union are continuing.
The union's negotiators will meet shortly to discuss the scope of industrial action in the event that the deadlock is not resolved.
Toll emphasised that the result of the ballot did not mean strike action was inevitable.
Toll chief executive Brian Kruger told investors last week that the two sides were close to reaching an agreement over a new four-year deal.
Mr Kruger has said he believes there is a solution to the main sticking point over the enterprise agreement's coverage, and has emphasised there was not a big disagreement over wages.
Toll has offered a 3 per cent increase in the first year of the new agreement, following by yearly rises of 4 per cent for the remainder of the four-year deal.
It has also offered to increase superannuation contributions by 0.75 per cent to 12.25 per cent, and to make at least 300 casual workers permanent in the first year of a new agreement.
The union wants super to be increased to 15 per cent by the end of the four-year agreement.