(Reuters) - The workers union representing more than 10,000 Starbucks baristas said they have authorized a potential strike, ahead of this year's final round of bargaining talks with the coffee giant on Tuesday.

Workers United, which has a bargaining delegation that represents workers at 525 Starbucks stores in the United States, said the coffee giant has yet to bring a comprehensive economic package to the table, while hundreds of legal disputes over unfair labor practices remain unsettled.

The union, which has been urging Starbucks to increase wages and staffing at its stores as well as implement better schedules, said it had not yet decided on when to go on strike.

Starbucks did not immediately respond to a Reuters request for comment.

Negotiations between Starbucks and Workers United began in April on a "foundational framework" to guide collective bargaining in the country and potentially settle pending legal disputes.

The previous round of negotiations took place in September, just weeks after former Chipotle Mexican Grill top boss Brian Niccol's surprise appointment as Starbucks' chief.

Ahead of the September talks, Niccol, in response to a letter by some baristas from the bargaining delegation, said he was committed to "engage constructively" with the union.

As of Sept. 29, the coffee chain has more than 11,000 company-operated stores in the U.S., employing about 200,000 workers, according to an annual filing.

This week, Starbucks raised its paid paternal leave by up to 18 weeks from 6 weeks for workers at its company-operated stores, which would be applicable from March.

The coffee chain is in the midst of a turnaround as Niccol works to bring back "coffee house culture" at Starbucks by implementing an overhaul of its cafes, by adding more comfortable seating, reducing customer wait time to less than four minutes, and simplifying its menu.