If no breakthrough was made at this ministerial-meeting, the seven-year-old Doha Round may collapse, analysts say.
At Monday's meeting, Sun said China has made a great contribution to the success of the Doha Round.
"We are committed in this Round to further cutting down our tariffs, the applied tariffs deeply," Sun told ambassadors and ministers at the meeting.
"We are making contributions of 50 percent of the total developing countries in terms of applied tariff rate cuts. So that is our contribution," he added.
According to the ambassador, developed countries like the United States are requiring extra concessions from developing countries while themselves are not playing the widely expected leadership role in the trade talks.
"They will cover all their sensitivities through various measures while they are asking China to participate in sectors where we have great sensitivities, particularly in chemicals, in electronics, in machinery," Sun said.
"So they have protected their sensitivities very well and now they ask us in our sensitive areas: 'you need more efforts to walk on extra miles there'," he said.
Sun insisted that on important issues such as SPs (special products) and SSMs (special safeguard mechanisms), which affect millions of poor farmers, China cannot really make further concessions.
He said China will continue to make great contributions to the talks, but major players also have to show flexibility.
(Xinhua News Agency July 29, 2008)