The organizers of a failed unionization drive at an Amazon warehouse in Alabama said Monday it petitioned for a new vote, claiming the tech and e-commerce giant improperly interfered with the election.

The Retail, Wholesale and Department Store Union said it filed objections Friday with the National Labor Relations Board, claiming that Amazon "created an atmosphere of confusion, coercion and/or fear of reprisals and thus interfered with the employees' freedom of choice," a union statement said.

The bitterly contested mail-in vote to unionize was rejected by a two-to-one margin according to the tally earlier this month, a stinging defeat in the push to create the first labor union at a US-based Amazon facility.

The results capped a bruising months-long battle that has sparked intense debate over workplace conditions at Amazon, which has more than 800,000 US employees.

The RWDSU said it filed 23 objections ranging from the placement of a collection box outside the facility which could allow the company to monitor voting, threatening layoffs or loss of benefits, intimidation and other improper actions.

Amazon, which has repeatedly denied any impropriety, did not immediately respond to an AFP request for comment.

The company has argued that most of its workers don't want or need a union and that it already provides more than most other employers, with a minimum $15 hourly wage and other benefits.

Amazon founder Jeff Bezos said last week that despite the vote, Amazon needs to do more for its employees.

"While the voting results were lopsided and our direct relationship with employees is strong, it's clear to me that we need a better vision for how we create value for employees -- a vision for their success," he said in his annual letter to shareholders.

rl/ft