Some underwear companies have even created sub-brands specializing in larger bra sizes.

Most lingerie companies say they started producing the larger bras within the last year.

Hong Kong-based Embry Group, for instance, began reacting to the trend last year by halting production of small-sized bras for some of its product lines.

"We don't produce A-cups for some bras with larger chest circumference now as demand is low," said Li Na, an official with Embry, which has counters in most of Shanghai's department stores.

"At the same time, we increased production of C, D and E-cup products and also found sales booming," she said.

Zhang Jing, a saleswoman with the Triumph brand at Landmark Plaza said she's surprised to find many women under the age of 20 need bras with C, D or even E-cups.

"It's so different from the past when most young women would wear A- or B-cup bras," she said. "You will never expect those thin women to have such nice figures if they are not plastic."

Taiwanese underwear brand Ordifen is another to act quickly.

Feng Wei, an official with the Ordifen's design, development and research department, said the company began making more C-cup products last year based on sales feedback and an internal survey.

"We make and sell products differently in various areas based on data collected in those places," said Feng. "For a time we only made A and B-cup bras for many categories of products but now C-cups have become a major focus especially in big cities like Shanghai and Beijing."

While there are no numbers to prove breast are growing quicker in large cities than underdeveloped areas, many salespeople say they have noticed that trend.

As sales of larger bras are busting out, Embry opened special counters for its bigger-cup bras under the sub-brand Comfort in February and is planning to set more of such outlets around the nation.

The Beijing Institute of Clothing Technology released a report last week saying the average chest circumference of Chinese woman has hit 83.53 centimeters, up nearly 1cm from the early 1990s. The growth trend is credited to women eating more nutritiously and taking part in more sports.