BANGKOK, Jan 10 (Reuters) - The sight of the first Japanese warships steaming in Asian waters since World War Two sent a shudder through China.

But for nations in Southeast Asia, fearful of China’s growing influence, that alone was one reason to welcome Japan’s new military role — albeit cautiously.

The other, is that many Southeast Asian nations are wary of U.S. dominance and an American tendency to focus too closely on its own agenda. "A strong factor, if not the main factor, is exactly the one the Chinese object to," Robert Karniol, Asia-Pacific editor of Jane’s Defence Weekly, told Reuters as Japanese Prime Minister Junichiro Koizumi toured Southeast Asia.

"By Japan expanding its role, the countries in the region see it as balancing an over-dominant Chinese influence," he says.

"Far from any nervousness on the part of any (Southeast) Asian governments or security services, they are most encouraging of Japan taking an expanded role in ensuring stability and security in the region."

Scarred by memories of Japanese military aggression and the brutal wartime occupation of much of the country, China sees any move by Japan to seek a military role beyond its own borders as a cause for protest.