An inner west pub is in damage control after a woman with cerebral palsy was denied entry and allegedly belittled and mocked by security staff who claimed she was intoxicated.

The Marlborough Hotel in Newtown apologised on Tuesday afternoon after patrons and friends of the woman, who was out celebrating her 21st birthday, flooded the venue's Facebook page with comments about the incident that unfolded early Sunday morning.

Friends said they would boycott the venue as a result and encouraged others to do the same.

The Marlborough Hotel in Newtown said in a post on Facebook it had' screwed up'. Credit:Fairfax Media

"My friend's beautiful and inspiring daughter was refused entry on the night of her 21st birthday," wrote Liane Gorham on the venue's Facebook page. "She suffers from cerebral palsy. Disgraceful and discriminating behaviour by your door staff. She was belittled and laughed at. Shameful!"