On Thursday, seven leading industrial nations, including the US, Britain, Germany, Japan and Canada, vowed to seal a series of free-trade deals, which Song said is an example of how Western countries try to maintain their authority in world trade rule-making.

Yu said the Doha round of talks touch on sensitive subjects such as subsidies for farm products that involve domestic political policies, which increases the difficulty in reaching a deal. But both Yu and Yi said China should stand firm on the multilateral trade system and play a constructive role with other emerging economies in shaping new global commerce.

"We must be clear that regional pacts can never replace multilateral ones," Yi said. "The multilateral system is the backbone and main channel of free trade and rule-setting, while regional cooperation serves as a supplement."

Yu said many subjects could not be negotiated under the regional system, such as farming subsidies. "Global issues can be solved only under a global system," he said.

"And the WTO is the only trade system with teeth," he added, referring to the WTO's dispute resolution function.

Yu also said it's easy to start regional talks but they might be hard to conclude, as the regional trade agenda is already hitting hurdles. The TPP is stalled over agriculture, and an EU-Canada deal has not been reached despite five years of talks.

"When the regional pacts are hitting the wall, it's time that countries return to the multilateral system," he said.

But Song Hong added that it's still hard to predict how seriously the regional system would affect the multilateral one. "I suggest China use the WTO as the main channel to push forward free trade but also actively participate in regional negotiations."

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