Mary-Louise Parker -- I Did NOT Threaten to Kill Antique Shop Owner

"Weeds" star Mary-Louise Parker adamantly denies calling a New York antique shop owner a "f*g" ... and threatening to have him KILLED ... despite the shop owner's accusations to the contrary.

A rep for MLP tells TMZ, the actress visited the Saugerties, NY antique store on January 2nd with her friend, who was owed a check by the shop owner for selling one of her purses.

The rep says the shop owner refused to pay Parker's friend ... and an argument ensued, during which the owner tried to take advantage of Parker's celebrity status by claiming she had threatened his life. The rep insists Parker had nothing to do with the fight.

In fact, the rep says as soon as it became clear to Parker that she was being roped into the situation ... Parker left.

As for the "f*g" accusation -- Parker's rep says anyone who knows the actress knows she would never say that word.

The owner -- a man named Daniel Seldin -- had filed an incident report with police following the alleged altercation, accusing Parker of threatening his life, saying, "DO YOU WANT TO WAKE UP TOMORROW? I'LL MAKE ONE PHONE CALL." Seldin said Parker also called him a "f*g."

We spoke to Seldin who insists his story is legit, adding, "I felt totally berated and violated." Seldin says he has since paid Parker's friend her money ... despite the incident.