Clinton had planned to meet senior Chinese officials on the sidelines of the East Asia summit in Hanoi, Vietnam on Saturday.
Her decision to accept a Chinese proposal for a Sunday visit to Hainan Island, and talks with State Councilor Dai Bingguo, reflects a crowded bilateral agenda that includes conflicts over exchange rates, trade and security issues.
U.S. Assistant Secretary of State for East Asian and Pacific Affairs Kurt Campbell, briefing reporters on the seven-country Clinton trip, said the stop on Hainan Island will last just a few hours and is aimed at resolving issues in advance of Mr. Hu's expected Washington visit.
"We believe it's very important to have a strong constructive relationship with China. Both sides recognize that. I think that most everyone in Asia appreciates the need for cool-headed constructive diplomacy between the United States and China in the current environment."
The New York Times newspaper reports that in the face of currency exchange and other issues, the Obama administration is stiffening its approach to China and trying to enlist allies to confront what was called a "newly assertive" Beijing.
When asked about the report, a senior State Department official said the United States is not trying to line up a bloc of countries against China. But he said Washington will not hesitate to address, if necessary in conjunction with like-minded governments, concerns it might have about Chinese policies.
Clinton is scheduled to meet Japanese Foreign Minister Seji Maehara in Honolulu late Thursday before heading to Hanoi where she will meet senior Vietnamese officials and have bilateral talks with summit delegates, including Chinese Premier Wen Jiabao.
After the Hainan Island stop, the secretary will visit Cambodia, Malaysia, Papua New Guinea, New Zealand and Australia in her sixth and most extensive Asia-Pacific trip since taking office.
Assistant Secretary Campbell said Clinton's agenda includes what U.S. officials say are flawed plans for elections in Burma next month, and efforts to draw North Korea back into Chinese-sponsored nuclear talks.
Campbell said it is too early to say what effect the apparent start of a leadership succession process in North Korea will have on Pyongyang's policies.
"This is not something that is going to reveal itself overnight. It's going to take a substantial period of diplomacy, interactions and consultations with friends and allies. We expect that one of the issues that will come up in all of our stops is an opportunity to exchange views about what we are witnessing in terms of developments inside North Korea."
Campbell, who stressed the need for "coordination and discipline" among U.S. allies in their approach to North Korea, welcomed preliminary steps toward reconciliation between North and South in recent days.
He said Clinton is keen to discuss "the way forward" when she meets with South Korean President Lee Myung-bak at the Hanoi regional summit.