Sept 9 (Reuters) - The union representing pilots at package delivery company United Parcel Service Inc said it had urged them to vote to authorize a strike.

The Independent Pilots Association said on Wednesday that if the pilots voted in favor of authorizing a strike, its board would have the authority to request a release from federally mediated negotiations with UPS.

The National Mediation Board has been mediating since early 2014 in contract negotiations between UPS and its pilots union on issues related to compensation, pension and benefits.

Rival FedEx Corp and its pilots tentatively agreed last month on an amended collective bargaining agreement after nearly a year of mediation from the National Mediation Board.

"UPS has stalled and delayed, unnecessarily prolonging our negotiations," Independent Pilots Association President Robert Travis said in a statement. "UPS management has created a bitter standoff with its pilot employees."

The contract is under the Railway Labor Act, the U.S. labor law that governs railroads and airlines, and it became amendable towards the end of 2011.

If the National Mediation Board grants a release from the mediation, a strike or lockout could follow after a 30-day countdown.

UPS said it continued to negotiate "in good faith" for a contract and it was confident that the talks would be completed without disruption in its services.

"Despite the (union's) announcement, there is no real threat of a strike. Such authorization votes are routine during negotiations in the airline industry, but they are legally irrelevant under the Railway Labor Act," UPS spokesman Mike Mangeot said in an emailed statement.

Even if the National Mediation Board grants the union a release from the talks, there are a "series of fail-safes, including presidential and congressional intervention, designed to prevent an interruption in operations," Mangeot said.

UPS shares closed at $97.93 on the New York Stock Exchange on Tuesday.

(Reporting by Ankit Ajmera in Bengaluru; Editing by Kirti Pandey)