Miss Lisa Chew (centre), flanked by her friends, Miss Lydia Ang (left) and Miss Ace Chong, at the Fill My Cups event at OverEasy.
Women with A cups got one drink, B cups got two and C cups got three.
Ms Cheryl Ho, spokesman for The Lo & Behold Group, admitted that the company was concerned that some people might find the event offensive.
She said: "Our stance is that it's all good fun, not sexist, not sleazy. No girls are going to get touched and we are not asking them to flash themselves."
Some felt it was distasteful however for OverEasy to give more free drinks to women with bigger breasts.