Disobedient visitors are preventing the China Pavilion - the most popular attraction at Expo 2010 Shanghai - from reaching full capacity, pavilion directors said on Thursday.

Eager visitors, who are not waiting to enter the pavilion at their allotted times, have caused the pavilion to only accommodate 38,000 people per day in the past two weeks, 12,000 short of its maximum capacity of 50,000 visitors per day.

"Many visitors come to the pavilion without obeying the time printed on their reservation vouchers," China Pavilion director Xu Hubin said at Thursday's press conference. "They always arrive earlier and form lines in the morning, which puts a lot of pressure on the pavilion's operation."

As a result, the show in the pavilion is delayed and the elevator transportation is affected. Organizers have called on visitors to obey their booked time slots to help maximize the pavilion's accommodation capacity.

Standing in the center of the Expo site, the China Pavilion is 69-meters high - triple the height of nearby pavilions. It has a floor space of 160,000 square meters, while other pavilions are only a few thousand square meters.

Its centerpiece is a 128-meter-long animated rendition of the famous painting Riverside Scene at Qingming Festival by Zhang Zeduan, a renowned Chinese painter of the Song Dynasty (AD 960-1279).

The structure can accommodate 50,000 visitors a day. However, with an average of 16,000 visitors a day in the past two weeks, only one in three visitors is able to enter the China Pavilion.

To avoid crowding, organizers are sending staff to distribute reservation vouchers at each Expo entrance, but the vouchers are gone soon after the Expo opens every morning, forcing many to skip the event's most popular attraction.

At Thursday's press conference, Expo spokesperson Xu Wei reiterated the "open and fair" process in the printing and distribution of the vouchers.

"About one-third of these tickets are allotted to group visitors, while the rest are distributed to individual tourists," he said.

Vouchers are printed in accordance with the pavilion's accommodation capacity the previous day.

Organizers said they are developing a plan to keep the China Pavilion open after the Expo, which is due to end on Oct 31, and vowed to put forward a more efficient approach to serve visitors wishing to see the pavilion.

Visitors can also tour the China Pavilion and other structures online at http://www.expo.cn, where a 3D version of the China Pavilion will be uploaded soon.