*To succeed, China, U.S. have to work together-Obama

*He says he will raise currency issue with China

*Obama will ask Beijing to do more to open markets

*Also looking for progress on climate ahead of Copenhagen

*Rejects criticism of stance on human rights in China

By Simon Denyer and Caren Bohan

WASHINGTON, Nov 9 (Reuters) - The United States sees China as a vital partner and competitor, but the two countries need to address economic imbalances or risk "enormous strains" on their relationship, President Barack Obama said on Monday.

Three days before leaving on a nine-day trip to Asia, Obama said the world's two most powerful nations need to work together on the big issues facing the globe, and any competition between them has to be fair and friendly.

"On critical issues, whether climate change, economic recovery, nuclear nonproliferation, it is very hard to see how we succeed or China succeeds in our respective goals, without working together," he told Reuters in an interview.