Bridgestone Japan's Firestone unit and its largest union reportedly said on Thursday they have broken off talks on a new labour contract, raising the possibility of a strike.

According to the Reuters news agency, the tyre maker had asked the union for concessions, including pension and health care benefit cuts, late last month.

"We informed the company that as long as their proposal remains, there's no way we're going to come to the bargaining table," Wayne Ranick, a spokesman for the United Steelworkers of America, which represents about 6,000 workers at Firestone's eight US plants, told Reuters, adding: "It is so far off the mark."

Ranick reportedly added that the union is considering its options and members have already authorised negotiators to call a strike.

Firestone, of Nashville, Tennessee, reportedly said it was disappointed with the union's decision to walk away from the table.

"Our proposal was made in good faith," spokesman Dan MacDonald told Reuters, adding: "We are ready, willing and able to return to negotiations whenever the union leadership is prepared to deal with the hard issues facing both of us."

The news agency said the company declined to comment on the specific terms of its proposal but said it needs an agreement that allows it to remain "competitive."

Reuters said no new talks are scheduled as a result - the previous contract expired on April 23 and has been extended day by day though either side can change that with a five-day notice.

The report said talks between the two sides had started in March, but were tabled until the Steelworkers could complete negotiations with Goodyear Tyre & Rubber Co.

A new three-year agreement ratified by Goodyear workers in September gave the union a seat on the company's board, some job security and profit-sharing in exchange for a wage freeze and increased worker payments for health care, Reuters said, noting that Firestone has rejected the Steelworkers' request to use the Goodyear agreement as a template for its new contract.