Las Vegas — A spokeswoman for MGM Resorts International says the company received a grievance regarding its relationship with Uber and its effect on doormen at its Las Vegas properties.

The Las Vegas Sun obtained a copy of the complaint where doormen claim that the alleged partnership with Uber violates their union contract and is costing them opportunities for tips.

MGM and the Culinary Workers Union Local 226 both tell the Las Vegas Sun ( that there are tensions between Uber and doormen at MGM properties entrances. Uber declined to comment.

Union spokeswoman Bethany Khan says that the organization is working to address the issue.

A statement from MGM spokeswoman Mary Hynes, the company will allow a grievance process where the parties can work out any issues.

Information from: Las Vegas Sun,