Tracy Morgan 'jokes about mentally disabled on stage'

Tracy Morgan has once again caused controversy by reportedly joking about the mentally disabled during a recent comedy show.

The 30 Rock actor was forced to apologise earlier this month after he engaged in a series of anti-gay remarks during a Nashville concert.

Morgan expressed his regrets for the offensive comments by meeting with LGBT teenagers and returning to Nashville to ask for forgiveness from those he angered.

During his first gig since the scandal erupted at New York City's Carolines Comedy Club last weekend, Morgan is believed to have received groans and some disapproval when he allegedly told his audience: "Don't ever mess with women who have retarded kids... Them young retarded males is strong. They're strong like chimps!"

Morgan apparently went on to make a joke about his unpleasant experience having sex with "a cripple" who was afflicted with a variety of health problems, an eyewitness disclosed to E! Online.

A rep for The Arc, an advocacy group for people with intellectual and developmental disabilities, has now called on Morgan to atone for his remarks.

Arc CEO Peter Berns said: "Tracy Morgan should apologise immediately. This quote is far too offensive to be excused as comedy, and it is very hurtful to people with intellectual and developmental disabilities and their families.

"Mr Morgan has an incredibly powerful platform from which to fix this, and if he's learned anything in the last few weeks, he can't bomb this apology."

Morgan has not yet offered any comment.