But with some government officials recently saying they are willing to research the TPP, China's attitude seems to be changing.

Tian Deyou, deputy director-general of the Department of American and Oceanian Affairs with the Ministry of Commerce, agreed. The Chinese government realizes it's time to change its mind on the matter, he said.

In May, the US Under Secretary of Commerce for International Trade, Francisco J. Sanchez, said the United States would welcome China joining the TPP.

In response, Shen Danyang, a spokesman for the Ministry of Commerce, said China will analyze the possibilities of joining the pact, and assess the pros and cons based on research and the principles of equality and mutual benefit.

Hong Lei, a spokesman for the Ministry of Foreign Affairs, said China is open to all trade pacts that boost the integration and prosperity of the regional economy in Asia, including the TPP.

But there is a long way to go before China could eventually join, as the pact would involve the core interests of many sectors including finance, foreign exchange and State-owned enterprises, Tian said.

Arvind Subramanian, who researches trade issues at the Center for Global Development and the conservative Peterson Institute for International Economics in Washington, said: "It's not clear to me that the US wants China in the TPP, at least during the negotiating phase, if the whole premise of this is asymmetric globalization. If China is in on the negotiations, they could sink because China's too big."

With the Doha round of talks under the framework of the World Trade Organization, which were launched more than 10 years ago, stalled, countries worldwide are pursuing new market openings through bilateral and regional trade pacts.

The objective of the Doha round is to lower trade barriers around the world.