Making it clear that the US was not trying to create divisions in Asia, Defence Secretary Ashton Carter has said America wants China to be part of the Asian security system and not stand apart from it.

Speaking to reporters aboard USS Theodore Roosevelt in South China Sea, Carter refuted reports that the United States is trying to create divisions in Asia.

"We're not trying to make divisions. We want China to be part of the security system of Asia and not to stand apart from it. That's why I accepted the invitation of President Xi extended to me to visit China," Carter said yesterday.

"I told the Chinese defence minister yesterday that I accepted that. I look forward to coming there. I believe that discussions with China, military to military contact with China, making sure that nobody does anything or has any misunderstandings out here. All that's a critical part of the job of keeping peace and stability out here and this here reflects that," he said.

Referring to his meetings with the defence ministers of the region including that with India, Carter said the American approach to a security structure for Asia is an inclusive one.

An American ship in South China sea is not unusual at all, he said.

"An American warship in the South China Sea, that's been going on for decades. And so, my visiting with defence ministers of other countries in this region is not a new thing," he said.

"The United States has long had a lot of key alliances and partnerships out here. If it's being noted today in a special way, it's because of the tension in this part of the world, mostly arising from disputes over land features in the South China Sea," Carter said.

Most of the activity over the last year being perpetrated by China, he alleged.

"So there is a lot of concern about Chinese behaviour out here and that was signified in a meeting I was just present at," he said.

"And many countries in the region are coming to the United States and asking us to do more with them so that we can keep the peace out here. So this is a symbol and a sign of the critical role the United States' military power play what is a very consequential region for the American future," Carter said.