"China never extended an invitation to the Philippine president," it said in a statement sent to The Associated Press.
Speaking Wednesday, Aquino told reporters: "You may be surprised, I will travel next week. It's quite a long trip to China. I will leave at 5 in the morning and will be back at 5 in the afternoon."
"I don't want to overstay our welcome there," he added.
The Philippines is this year's "country of honor" at the trade fair, which takes place in China every year to highlight trade exchanges between Beijing and the 10-member Association of Southeast Asian Nations.
The Philippines and China have been embroiled in increasingly antagonistic territorial disputes in the South China Sea. Last year, China seized a shoal near the northwestern coast of the Philippines, and this year it demanded that the Philippine navy withdraw from Second Thomas Shoal farther south.
The Philippines has incensed China by seeking U.N. arbitration to solve the disputes.
Ian Storey from the Institute of Southeast Asian Studies in Singapore said China's action would lead to a further deterioration of ties with Manila and reflects Beijing's readiness to resort to punitive diplomatic and economic steps after the Philippines sought international arbitration.
"The trade fair has always been an important occasion for ASEAN leaders to visit China and meet with the Chinese premier on the sidelines," Storey said. "This year, politics has trumped economics."
Dwarfed by China's mammoth military, the Philippines also has started negotiations with Washington to allow a larger number of U.S. troops to have access to local military camps, where they could pre-position ships, assault helicopters and high-tech surveillance aircraft in close proximity to the South China Sea.
China sought to use economic pressure to sway Manila, and in the latest sign of Beijing's growing assertiveness, reorganized its coast guard to beef up its ability to police its maritime claims.
The visit's cancellation was announced as China was hosting ASEAN foreign ministers ahead of talks in China next month on how to implement a 2002 agreement on peacefully handling disagreements.
Referring to the South China Sea territorial dispute, Thai Foreign Minister Surapong Tovichakchaikul told reporters that ASEAN anticipated the September discussions would be "constructive and substantive."
ASEAN nations have been pushing for a code of conduct governing interactions in the area, but China has been reluctant to negotiate with the group as a whole, preferring to deal with nations bilaterally as a way of bringing its full size, economic influence, and political heft to bear on its much smaller neighbors.
China claims virtually the entire South China Sea and its island groups on historical grounds. The Philippines, Vietnam, Brunei, Malaysia and Taiwan have rejected that, sparking fears that the disputes might turn violent.
Chinese Foreign Minister Wang Yi reiterated China's reluctance to discuss territorial disputes with ASEAN as a bloc, while emphasizing the importance Beijing places on regional stability.
"We do not believe one individual position should replace that of ASEAN, and cannot let our own individual relations be affected by one's selfish interests," Wang said.
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Associated Press writers Jim Gomez in Manila and Christopher Bodeen in Beijing contributed to this report.
