China and the United States have agreed to deepen a dialogue on nuclear and Asian security issues following the end of high-level talks in Beijing this week, the US defence department said on Saturday.

The discussions were part of ongoing Sino-US defence consultations aimed at increasing mutual understanding and avoiding miscalculation between the two powers, said David Sedney, deputy assistant secretary of defence for East Asia.

"We had very positive discussions on that (nuclear strategy and policy) and we expect to be moving forward with that dialogue very shortly," Sedney said at a press briefing in Shanghai.

"We also had an in-depth exchange of each other's views of Asian security issues – that will lay the basis for us continuing that kind of discussion that we both agree is very important."

The talks were followed by a signing on Friday of two agreements announced earlier this week between the countries.

The first gives Washington access to Beijing's military archives to search for missing servicemen from conflicts since World War II.

The other was an agreement to establish a telephone hotline between the two armies, which is expected to be operational in about a month, Sedney said.

The military hotline was first suggested by the United States in 2003, and US President George W. Bush reached agreement on the link when meeting his Chinese counterpart Hu Jintao at a regional forum in Sydney in September.

The two nations discussed the issue further in November last year when US Defence Secretary Robert Gates visited Beijing.

US and Chinese heads of state have been able to communicate over a similar line since the late 1990s but the new hotline will be China's first direct military telephone link with another country.

Sedney said it aims to reduce misunderstandings between the two militaries, although its effectiveness and exact use was still to be determined.

"In terms of specifically how we use it, for what issues and at what time is something we will have to develop with the Chinese.

"The purpose is to address emergency, crisis or important issues that need immediate communication," said Sedney, adding that the line would have come useful amid tensions between Beijing and Washington last year.

Sino-US relations remain tetchy despite warming dramatically since spiralling to a low in 2001 when Chinese jet fighters collided with a US Navy surveillance plane forcing it to land on Chinese soil.

The US Pentagon remains irked by a Chinese military build-up that it believes is aimed at thwarting American intervention in a conflict over Taiwan, and ultimately challenging its access to the region.

US suspicions intensified in January last year after a Chinese anti-satellite test in which a ballistic missile was used to destroy a Chinese weather satellite in low Earth orbit.

And in a flare-up in November, Beijing denied US warships port entry in Hong Kong, a decision that Sedney said the Chinese have never adequately explained.

Meanwhile, China called on the US earlier this month to provide more information about its shooting down of a defunct US spy satellite, amid concerns about space security.