Chad Coleman/Bellevue Reporter

ABC News' Melissa Morrissette and Kevin Dolak report:

A Washington mail carrier is fighting back after he was told by a supervisor that he is no longer allowed to wear a Santa Claus suit while delivering the mail.

Letter carrier Bob McLean has been donning the Saint Nick costume for the holiday season while on his route in Bellevue, Wash. for over a decade. Now a supervisor has told him that he is no longer allowed to spread his brand of holiday cheer, alleging that a complaint was filed that he is not wearing official post office attire.

"The government is shutting me down because it's a non-postal regulation uniform," McLean, who has been working with the postal service since 1971, told The Bellevue Reporter.

McLean, who wears a white beard and has crisp white hair, said that he began wearing the costume when he was told by that he looks a bit like Kris Kringle. Since then he has delighted residents while delivering the post, even causing traffic jams as motorists try to get a peek. He regularly visits the Aegis Living of Bellevue senior center as Santa, and at Bellevue's most popular Christmas attraction, Snowflake Lane, people lined up to take photos with him.

But this year he was told that he must stop, and he's not taking the news sitting down. USPS spokesman Ernie Swanson said the complaint came from a fellow carrier; McLean says that he believes it may be management's decision, but he is unable prove it. No one has come forward and said they had a problem with his costume, he told ABC News.

McLean told said that the first reason that he was given for not being able to wear the suit was safety, followed by the fact that it was not a proper uniform. Finally a direct order came down, which he says he couldn't disobey.

"This was the first time; I don't know what happened. I don't step on anyone's toes," he said, adding that dressing as Santa isn't religious to him, "it's secular. It's about giving."

His union has now filed a grievance over the matter, and will have a meeting Thursday morning to discuss the matter, th0ugh he expects it will get stonewalled until after the holidays.

Meanwhile, he continues to wear the Santa hat and will also wear thermo and white gloves on Saturday.

"I am wearing it no matter what," McLean said, adding that he has even noticed supervisors watching him to make sure he doesn't wear the suit while he delivers mail.

Despite the setback, McLean says that he still has his Christmas spirit, which he says his supervisors can't take it away. On Christmas eve he says he plans to ride up and down Bellevue Way, waving to residents as he usually does in his red PT Cruiser, dressed like Santa.