* Euro dips, still fragile after rebound from 4-yr trough
* Persistent euro zone fears shadow markets
* Asian stocks touch 3-month low; Nikkei claws higher
* European stocks set to rise - financial bookmakers
By Elaine Lies
TOKYO, May 18 (Reuters) - The euro dipped on Tuesday, struggling to pull away from four-year lows hit on Monday, and Asia stocks fell to three-month lows as persistent worries about the euro area's fiscal health weighed on investor sentiment.
China's key stock index, among the world's worst performers this year due to fears of monetary tightening, rose more than 1 percent in seesaw trade that took it in and out of negative territory after Monday's 5 percent tumble, its biggest one-day fall for eight months.
European shares were set to edge higher, boosted by late buying on Wall Street that left indexes steady on the day. Financial spreadbetters called Britain's FTSE 100 to open as much as 0.4 percent higher and Germany's DAX to rise as much as 0.6 percent.
News that the U.S. Senate had voted on Monday for the U.S. government to oppose International Monetary Fund bailouts to countries unlikely to repay was the latest news to weigh on the beleaguered euro.
"Even small factors can prompt selling of the euro on rallies at the moment. After its failure to clearly break above $1.2400 yesterday and today, the market may have taken the news as a factor," said Daisuke Karakama, market economist at Mizuho Corporate Bank.
"But if the market had taken this to mean the United States will really exercise veto power, the euro could have fallen further," he said.
The euro fell 0.3 percent to $1.2360, having pulled up from a four-year low of $1.2234 on Monday. Against the yen, the euro fell 0.3 percent to 114.41 yen.
Euro zone finance ministers said they will try at a meeting on Friday to iron out wrinkles in a 750 billion euro ($929 billion) emergency plan they hatched last week.
Traders said that while the euro's sharp fall made it ripe for a bounce, it would stay under pressure over the longer run due to concerns that belt tightening needed to prevent the Greek debt crisis from spreading could stunt European growth.
"It's still hard to see how the problems in Europe stemming from Greece will come to an end. It's hard to say what would convince everyone that it's over," said Minoru Shioiri, chief manager of FX trading at Mitsubishi UFJ Morgan Stanley Securities.
Shioiri noted that costs of insuring Portuguese and Greek government debt jumped on Monday.
CHINA TROUBLES
Increasing worries about China were also troubling Asian markets after a Chinese leading economic indicator on Monday showed that growth may already have peaked in the world's third-largest economy.
China's main Shangahi stock index fell 5.1 percent on Monday to its lowest close in a year and marking its biggest one-day fall in eight months.
It was up 1.3 percent in Tuesday afternoon trade after hitting a one-year low earlier.
The MSCI index of Asia-Pacific shares outside of Japan was down 0.1 percent after earlier touching a three-month low and falling roughly 3.3 percent the day before.
In choppy trade, many markets swung between losses and gains. The Nikkei dipped into negative territory during the last hour of trade as losses in Asian shares picked up steam, before finally closing up on the day just 0.1 percent.
Seoul shares shed 0.5 percent but Australian shares edged up 0.2 percent. Singapore and Hong Kong showed modest gains, while Taiwan and Mumbai were lower.
Fund managers said European woes were weighing on markets, with materials and consumer discretionary shares the worst-hit.
"I can't see a catalyst that's going to drive the market much higher in the next couple of months," said ATI portfolio manager Simon Burge.
"It's going to be a long time before we get an earnings recovery in Europe, and U.S. companies have a massive exposure to Europe."
Samsung Electronics, the world's largest memory chip maker, said it will invest a record $16 billion this year to boost output of chips and flat screens.
The move slightly boosted Japanese chip-gear makers, such as Advantest Corp, but weighed on Hynix Semiconductor and LG Display, on expectations the new investment would widen Samsung's gap with smaller rivals.
Gold edged up to stand around $20 below a lifetime high struck last week. Spot gold was at $1,225.80 an ounce by 0553 GMT.
Crude oil rose from 5-month lows hit on Monday but the trend remained uncertain due to investor jitters about the euro currency and swollen U.S. oil inventories.
NYMEX crude for June delivery gained 59 cents to $70.66 a barrel.
(Additional reporting by Aiko Hayashi and Masayuki Kitano in Tokyo, and Sonali Paul in Melbourne; Editing by Neil Fullick)