(Reuters) -Starbucks ( SBUX ) baristas' union said on Thursday it would vote on whether to authorize an unfair labor practice strike at unionized locations to demand that the company return to the negotiating table.

Contract talks between the coffee-chain giant and the union, which represents more than 12,000 baristas, began last year, but have hit an impasse.

"If they're ready to come back, we're ready to talk. Any agreement needs to reflect the reality that Starbucks ( SBUX ) already offers the best job in retail," Jaci Anderson, Starbucks' ( SBUX ) director of corporate communications told Reuters.

Last week, New York City's Comptroller and other Starbucks ( SBUX ) shareholders wrote to the company to resume talks with its workers' union.

The Starbucks Workers United union said the voting will begin on Friday and baristas were preparing to strike in about 60 cities, as they demand a contract that reflects "improved staffing, better pay and on-the-job protections."

Union workers represent a small fraction of the company's U.S. store staff but the voting comes ahead of the crucial holiday season amid CEO Brian Niccol's turnaround efforts.

During the holiday season last year, unionized Starbucks ( SBUX ) baristas went on a five-day strike, which closed some cafes in Los Angeles, Chicago and Seattle, although the company said there was no significant impact to store operations at the time.

In April, union delegates voted to reject Starbucks' ( SBUX ) proposal that guaranteed annual raises of at least 2%, which the Workers United said did not offer changes to economic benefits such as healthcare or any immediate pay hike.

Hourly workers at Starbucks ( SBUX ) currently earn an average of $30 per hour, while benefits include college tuition paid for upfront and healthcare, a Starbucks ( SBUX ) spokesperson told Reuters.

There are over 650 unionized Starbucks ( SBUX ) stores currently in the U.S., according to the union's website, up from about 525 in December last year.

(Reporting by Juveria Tabassum in Bengaluru; Editing by Sriraj Kalluvila)