(Reuters) - Pressure is building on Amazon.com ( AMZN ) to come to the bargaining table with the Teamsters Union as thousands of workers threaten to strike during the retailer's busy holiday selling season.

Workers in New York City, southern California and Skokie, Illinois, voted in recent days to authorize a strike should Amazon ( AMZN ) fail to bargain with the International Brotherhood of Teamsters. On Wednesday, the union said workers at an Atlanta Amazon facility became the eighth to vote in favor of striking, and the union has threatened to call a strike at any time.

The Teamsters, which claim to represent 10,000 U.S. Amazon ( AMZN ) workers at 10 facilities, have said Amazon ( AMZN ) has ignored their requests to meet to reach a contract, despite setting a Dec. 15 deadline.

With over 700,000 workers at around 1,000 warehouses scattered around the U.S., a strike is unlikely to cripple Amazon's ( AMZN ) operations, but such a walkout in the final few days before Christmas could create supply chain hiccups and send a signal that the Teamsters intend to inflict financial harm.

Still, say experts, Amazon ( AMZN ) would likely be unwilling to meet or negotiate with the Teamsters as it could open the door to further organizing efforts.

"Amazon ( AMZN ) clearly has developed a strategy of ignoring their workers' rights to collectively organize and negotiate," said Benjamin Sachs, a Harvard Law School professor of labor and industry. He noted that more than two years have elapsed since workers in Staten Island successfully voted to become the first U.S. warehouse to unionize and the company has yet to acknowledge them.

An Amazon ( AMZN ) spokesperson did not immediately respond to a request for comment. The Seattle-based company has previously said the Teamsters "attempted to coerce" workers illegally to join the union and that the union does not represent as many Amazon ( AMZN ) employees as it claims.

Amazon ( AMZN ) has successfully resisted several unionization drives over the years, including a failed 2021 vote at a warehouse in Bessemer, Alabama, that is still being contested. An administrative judge last month ordered a third union election in Bessemer after ruling Amazon ( AMZN ) had acted unlawfully to thwart the vote there.

Workers have said Amazon's ( AMZN ) emphasis on ever greater speed and efficiency can lead to injuries, while the company has said it pays industry-leading wages and regularly introduces automation designed to cut down on repetitive stress. Having to face union demands could make it harder for Amazon ( AMZN ) to hire and fire warehouse workers and raise costs to employ them.

"Anything Amazon might do to acknowledge these workers gets them that much closer to having unions and they have very publicly resisted that," said Jake Rosenfeld, a sociology professor at Washington University in St. Louis who has studied unions. "By every indication they want absolutely nothing to do with unionization."

A spokesperson for the Teamsters said the group has not received any outreach from Amazon ( AMZN ).

Sachs and Rosenfeld said Amazon's ( AMZN ) multi-year delay in negotiating with its first union at a warehouse on Staten Island showed the weaknesses in labor law. "It's been a very successful strategy, the work continues there and there is still no contract," said Rosenfeld.

Amazon ( AMZN ), however, has not been idle. It filed its own objections with the National Labor Relations Board over the Bessemer union election, alleging bias among agency officials, among other issues. And the company has challenged the constitutionality of the NLRB itself in a September federal lawsuit.

John Logan, a San Francisco State University professor of labor and employment studies, said a strike before Christmas may be the Teamsters' last opportunity to make an impact before anticipated changes to labor law under the incoming Trump administration.

"Even a smaller strike could cause some inconvenience for Amazon ( AMZN )," he said.