In the early years of China's rise to economic and military prowess, the guiding principle for its government was Deng Xiaoping's maxim: 'Hide Your Strength, Bide Your Time'.

Now, more than three decades after paramount leader Deng launched his reforms, that policy has seemingly lapsed or simply become unworkable as China's military muscle becomes too expansive to conceal and its ambitions too pressing to postpone.

The current row with Southeast Asian nations over territorial claims in the energy-rich South China Sea is a prime manifestation of this change, especially the standoff with the Philippines over Scarborough Shoal.

"This is not what we saw 20 years ago," said Ross Babbage, a defence analyst and founder of the Canberra-based Kokoda Foundation, an independent security policy unit.

"China is a completely different actor now. Security planners are wondering if it is like this now, what is it going to be like in 20 years time?"

As China also continues to modernise its navy at breakneck speed, a growing sense of unease over Beijing's long-term ambitions has galvanized the exact response Deng was anxious to avoid, regional security experts say.

In what is widely interpreted as a counter to China's growing influence, the United States is pushing ahead with a muscular realignment of its forces towards the Asia-Pacific region, despite Washington's fatigue with wars in Iraq and Afghanistan and the Pentagon's steep budget cuts.

And regional nations, including those with a history of adversarial or distant relations with the United States, are embracing Washington's so-called strategic pivot to Asia.

"In recent years, because of the tensions and disputes in the South China Sea, most regional states in Southeast Asia seem to welcome and support U.S. strategic rebalancing in the region," said Li Mingjiang, an assistant professor and China security policy expert at Singapore's Nanyang Technological University.

"Very likely, this trend will continue in coming years."

Last week, U.S. Defense Secretary Leon Panetta laid out the details of the firepower the Obama administration plans to swing to the Asia-Pacific region.

As part of the strategic pivot unveiled in January, the United States will deploy 60 per cent of its warships in the Asia-Pacific, up from 50 per cent now.

They will include six aircraft carriers and a majority of the U.S. navy's cruisers, destroyers, littoral combat ships and submarines.

REBALANCING

"Make no mistake, in a steady, deliberate and sustainable way, the United States military is rebalancing and bringing an enhanced capability development to this vital region," Panetta told the Shangri-La Dialogue, an annual security conference in Singapore attended by civilian and military leaders from Asia-Pacific and Western nations.

For some of China's smaller neighbors like the Philippines, there is a pressing urgency to build warmer security ties with Washington.

A two-month standoff between the Philippines and China over Scarborough Shoal shows no sign of resolution, with both sides deploying paramilitary ships and fishing boats to the disputed chain of rocks, reefs and small islands about 220 km (130 miles) from the Philippines.

Philippine President Benigno Aquino met President Barack Obama on Friday at the White House, where the two discussed expanding military and economic ties.

Obama later told reporters that clear, international rules were needed to resolve maritime disputes in the South China Sea.

While the standoff continues, reports last week in China's state-controlled media and online military websites suggested that the first of a new class of a stealthy littoral combat frigate, the type 056, had been launched at Shanghai's Hudong shipyard with three others under construction.

Naval analysts said the new 1,700-tonne ship, armed with a 76mm main gun, missiles and anti-submarine torpedoes, would be ideal for patrolling the South China Sea.

These new warships would easily outgun the warships of rival claimants, they said.

The type 056 is the latest example of an accelerated military buildup that allows China to dominate its offshore waters.

While these warships were designed for lower-level regional conflict, experts say one of the primary goals of Beijing's wider deployment of advanced, long-range missiles, stealthy submarines, strike aircraft and cyber weapons appears to be countering the U.S. military in the region.

"China is investing in a whole raft of capabilities to undermine the U.S. presence in the Western and Central Pacific," said Babbage, a former senior Australian defense official.

"It is a fundamental challenge to the U.S. in Asia."

Panetta and other U.S. officials routinely reject suggestions that the pivot is aimed at China but military commentators in Beijing appear in no doubt.

In a report last week on the U.S. military, the China Strategic Culture Promotion Association, a non-government security analysis group, said Beijing should be on alert in response to the U.S. military 'return to Asia' and any attempt to intervene in disputes in the South China Sea.

WATCHING BRIEF

In a separate commentary published in the state-controlled media, the group's executive vice president, outspoken retired Major General Luo Yuan, said the U.S. pivot was part of 'watching brief' on a rising China.

"The U.S. military has developed four different plans to combat the Chinese military," Luo wrote, but gave no details.

Luo, a government adviser, is one of a number of senior Chinese officials and commentators who have called for a more determined effort from Beijing to safeguard China's maritime interests.

This suggests China will become more assertive in the South China Sea but it is unlikely to use force, according to Nanyang University's Li.

"Beijing understands very well that any military confrontation would have a profound negative impact on China's strategic position in the Asia-Pacific and China's relations with regional states," Li said.

The worry however is that a mistake or a miscalculation could trigger a confrontation.

REACHING OUT

As part of his swing through Asia last week, Panetta also visited India and Vietnam in a bid to enhance security ties with two key regional powers that have not been traditional U.S. allies but are increasingly apprehensive about China's rise.

At Vietnam's deep water port of Cam Ranh Bay, a key U.S. base during the Vietnam War, Panetta said the use of this harbor would be important to the Pentagon as it moved more ships to Asia.

Later, in New Delhi, Panetta said ties between the two nations were improving rapidly but expanded defence cooperation was needed to boost regional and global security.

He said the United States planned to increase its military presence and defense partnerships in an arc from the Western Pacific, through East Asia, South Asia and into the Indian Ocean.

"Defense cooperation with India is a linchpin in this strategy," he said.

In a development that will be further cause for concern in Beijing, the fleshed-out U.S. pivot and renewed commitment to regional defense ties won strong endorsement from key allies, even those who rely on growing trade with China.

On a visit to Beijing, Australian Defence Minister Stephen Smith said the U.S. presence in Asia had been a force for peace, stability and prosperity since the end of World War Two.

"Australia welcomes very much the fact that not only will the United States continue that engagement, it will enhance it," he said in a speech to the China Institute of International Strategic Studies.

Smith noted that two-way trade between Australia and China reached $120 million last year but Canberra would continue to deepen its military ties with the U.S., including the rotational deployment of up to 2,500 U.S. troops through Darwin.

If the standoff over Scarborough Shoal is a guide to future territorial disagreements, Beijing can expect other regional nations to feel the same way.

"The South China Sea disputes are likely to remain as a regional security spotlight issue and it will continue to pester China's relations with those claimant states," Li said.