A Chinese naval training ship in Vietnam in April. (File photo/Xinhua)

Asia strategy expert Michael J Green says China's military forces have not been able to catch up with the US because the country has been over-reliant on overseas resources and sea lanes. The country also lacks strong allies, he said.

Green said the US may misjudge the situation and messages from Beijing. The Chinese military has modernized faster than the US estimated over the past five to 10 years and has developed key anti-access area-denial technology that could threaten America's military bases, said the former senior director of Asian affairs at the National Security Council of White House.

China's influence has grown beyond the island chain that includes Japan, Taiwan, the Philippines and Guam to the offshore waters in the Pacific Ocean near Japan, according to Taiwan's Central News Agency.

Yet compared to US forces, the Chinese army is less experienced in battle and only has allies such as Pakistan and North Korea, Green said. The country has also been relying heavily on shipping lanes to bring resources home. More than 90% of its resources are imported from channels in the Persian Gulf and Indian Ocean, according to Taiwan's Central News Agency.

It would be very difficult for the Chinese military to grow as strong as America's, but Washington should remain cautious and avoid misjudgment, said Green.