BEIJING/TAIPEI, Sept 18 (Reuters) - China's growing military strength, from stealth jets to aircraft carriers and anti-satellite missiles, has shifted the balance of power in the Taiwan Strait to Beijing's advantage, and this will not be materially affected by an imminent U.S. arms deal with Taiwan.
The duration of any potential conflict between China and Taiwan will be a matter of days, not weeks or months, analysts and experts say.
The Obama administration is expected to notify formally Congress next week on an arms package including F-16 upgrades for the self-ruled island China claims as its own, but not the new fighters Taipei wanted.
Beijing, meanwhile, has shown no sign of ending an arms build-up that is strategically focused on Taiwan, and analysts say the arms deal will do little to alter the balance.
China's military advances have continued despite a warming of ties across the narrow Taiwan Strait that followed the election of Ma Ying-jeou as president of the democratic island in 2008, and his signing of landmark trade and economic pacts.
Taiwan's military can do little to disguise its unease.
"There have also been no signs of adjustments to military deployments facing our country," Taiwan Defence Minister Kao Hua-chu wrote in July in the foreword to its annual white paper.
"We must build forces that are as impregnable as a rock."
The U.S. Defense Department's annual assessment to Congress last month warned that China "remains focused on developing the pre-requisite military capabilities to eventually settle the dispute on Beijing's terms".
Taiwan once held the military edge against a backward Chinese People's Liberation Army (PLA). Today, experts generally agree that in the event of conflict, Taiwan would have at most only a few days to hold off China and get help from outside, most likely the United States, if they were to stand any chance.
"No one's really asking the question, could Taiwan beat China in an all-out conflict," said Matt Durnin, a researcher with the World Security Institute.
"The question they're asking is whether or not Taiwan could survive long enough in a conflict it would be able to recruit other countries to support it politically or militarily."
China has not compromised on its long-term demand that Taiwan is sovereign Chinese territory and must eventually come under its control.
Beijing's military strategy, despite the warming of ties, remains focused on securing Taiwan, wrote security analyst Dean Cheng of the Heritage Foundation in Washington.
"Coupled with limitations on U.S. weapons sales, Taiwan is falling behind," Cheng said. "Worse, the steady modernisation of the PLA has not been matched by Taiwan."
Taiwan in the past was able to rely on China's inability to project power across the strait which separates them, its own technological superiority and the help of the U.S. armed forces in the event of conflict, who would easily outclass China.
"China's increasingly modern weapons and platforms threaten to negate many of those factors upon which Taiwan has depended," the Pentagon said, pointing to China's rapidly modernising navy and air force and new, formidable ballistic missiles.
Unlike China, Taiwan has no nuclear weapons, and only a small number of Patriot missiles to defend against any missile attack.
Meanwhile, China's military spending spree continues. Beijing in March said it would boost defence spending by 12.7 percent in 2011 to 600 billion yuan ($94 billion), marking a return to double-digit growth.
China downplays its spending, saying it is upgrading its outmoded forces and that its plans do not pose a threat to any country. It also notes its defence budget is far lower than that of the United States.
But President Hu Jintao has made modernising the navy a priority. China is upgrading its destroyers and frigates to provide capability to sail further and strike harder, and is developing fearsome anti-ship ballistic missiles to take out U.S. carriers.
Last month, China's first aircraft carrier made its maiden run.
Taiwan, which for years relied on better equipment and better training, has been hobbled by the refusal of any country aside from the United States to sell it weapons, fearing an angry response from China. The advantages it once maintained in the air slipped away over the past decade as China modernised.
Despite Taiwan's public calls for weaponry, defence spending has not kept pace. The NT$300 billion ($10 billion) earmarked for this year is just 2.2 percent of gross domestic product (GDP). Ma had promised in his 2008 election campaign to raise that to 3 percent.
The aging of Taiwan's fleet of fighters came into stark focus this week with the crash of two U.S.-built F-5 fighters, which it first put into service in the 1970s and still uses for training and reconnaissance missions.
The backbone of Taiwan's air force is made up of some 140 U.S.-made F-16s, about 60 French-built Mirage 2000s and about 130 Ching-kuo Indigenous Defense Fighters. Jets lost in accidents over the years are nearly impossible to replace.
This has spurred Taiwan's requests that the United States sell it 66 new F-16 C/D jets, a more advanced version of the ones they already operate.
The Taiwan-U.S. Business Council, which had lobbied for the sale of advanced weapons, said on Friday Obama had instead approved an upgrade for the existing fleet.
Without new jets, experts say, Taiwan would not last long in a conflict.
Training is the air force's strong suit, but experts say that a well-planned early Chinese missile strike could take out most Taiwan air base runways and leave the island's aircraft, hidden in fortified or mountain bunkers, trapped on the ground.
If the air force is old, Taiwan's navy makes it look like a paragon of modernity. It has four submarines -- two of which date from World War Two and still have some of their original brass fittings -- compared with more than 30 for China, including a few of which are nuclear powered. ($1 = 29.615 Taiwan dollars) ($1 = 6.392 Chinese yuan) (Additional reporting by Paul Eckert in Washington, Editing by Brian Rhoads and Raju Gopalakrishnan)