* SNB, fighting deflation risk, intervenes on franc -traders
* SNB committed to fighting rise in Swiss franc vs euro
* SNB's current policy is not to comment on intervention
* Analysts see 1.50 francs/euro as SNB's threshold
(adds traders reporting further intervention, recasts, adds market moves)
By Sven Egenter
ZURICH, June 24 (Reuters) - The Swiss National Bank repeatedly intervened in the currency market on Wednesday, traders said, giving a stark reminder that it is determined to fight deflation risks by preventing a rise in the Swiss franc.
The dollar shot up 3 percent on the day against the franc, on track for its biggest one-day gain since March 12, the day the SNB caught financial markets by surprise by accompanying monetary policy easing with intervention.
Both the SNB and the Bank for International Settlements (BIS) -- which traders said was apparently acting on behalf of the Swiss central bank by selling francs for dollars and euros -- declined to comment on the reported intervention.
Traders reported that the first wave of intervention came during the European session and as the U.S. trading day was beginning. More intervention was reported during the U.S. trading session.
The dollar rose as high as 1.1026 francs on electronic trading platform EBS by 1733 GMT, breaking the 1.1000 level for the first time since May 21. It last traded up 2.9 percent at 1.0986.
The euro was up 2.1 percent at 1.5336 francs on EBS. It climbed as high as 1.5381, nearly four centimes above the 1.50 level which many analysts see as the SNB's tolerance threshold.
During the first waves of intervention during the European session, traders said the BIS bought euros at 1.5010/15 francs and then again at 1.5125 francs. It later bought dollars at 1.0880 francs, they added..
ECHOES OF BOJ
The SNB has confirmed only one intervention so far when it launched the new measures on March 12.
However, last week it repeated its pledge to fight a franc appreciation, when it stuck to its full set of unconventional measures to fight a deep recession, which also include ultra-low interest rates and the purchase of bonds.
A traditional safe haven currency, the franc has risen 10 percent during the financial crisis, exacerbating the blow to the export-dependent Swiss economy from the global downturn.
The SNB's intervention tactics have prompted analysts to draw comparisons with the Bank of Japan's past tussles with the foreign exchanges to curb the strength of the yen.
"The SNB hasn't confirmed yet whether it intervened again today but its apparent selling of francs seems reminiscent of the BOJ interventions in 2003-2004 that drew a line in the sand at 100 in dollar/yen," UBS strategists said in a research note.
"The SNB strategy seems similar now: big interventions to put a floor under euro/Swiss franc at 1.50, warnings about Swiss franc strength and the risk of deflation as Japanese policymakers gave, franc sales to augment domestic quantitative easing, and finally waiting for a global economic rebound to reduce safe haven franc demand."
SNB KEEPS MUM
Analysts said intervention also fitted the SNB's renewed commitment expressed at its quarterly policy review last week.
"We believe that the Bank will stick to its intention of stabilising the franc, an intention that was repeated at the June monetary meeting last week," ING's Julien Manceaux said.
"Since then, the franc appreciated somewhat against the euro, approaching the 1.50 franc per euro threshold, triggering today's intervention," he said.
SNB board member Thomas Jordan said last week that the central bank would not comment on interventions, neither on volumes nor on levels or timing.
"There is no fixed threshold beyond which we become active; we simply decide in accordance with the situation at hand," Jordan said. "And markets should not become used to a certain level of intervention."
But Jordan, as well as his fellow-policymakers, emphasised that there was no end to the intervention in sight. "The aim of our buying foreign currency is to prevent an appreciation of the Swiss franc against the euro," he said. "This is the key component of our unconventional monetary policy."
The SNB has paid particular attention to the rise of the franc against the euro, the currency of its key trading partners.
Its concerns have been exacerbated as Swiss consumer prices fell at the fastest pace in 50 years in May, stoking fears the Swiss economy was heading for a harmful deflationary spiral of weakening demand and falling prices.
(Additional reporting by Swaha Pattanaik in London, Sam Cage in Zurich, Steven Johnson in New York; editing by David Stamp)