* Dollar index hits 7-mth high, euro/dollar at 8-mth low
* Risk aversion on euro zone debt woes, US payrolls in focus
* SNB seen selling francs in Asia, SNB, BIS decline comment
(Adds quotes, detail)
By Neal Armstrong and Naomi Tajitsu
LONDON, Feb 5 (Reuters) - The dollar hit a seven-month high against a currency basket on Friday, boosted by risk aversion as the cost of insuring the debt of some euro zone nations against default hit record highs on worries over their fiscal positions.
The euro fell to its weakest versus the dollar since May 2009 and was unable to sustain gains made against the Swiss franc after the Swiss National Bank was seen selling the domestic currency in Asian trade, which had lifted the euro from a 15-month trough.
The cost of insuring Greek, Portuguese and Spanish government debt against default rose to record highs according to monitor CMA DataVision, as fears about the fiscal health of peripheral euro zone economies mounted. [ID:nLDE6140LZ]
Analysts said market movements were being driven by a combination of euro weakness and dollar strength as investors also awaited U.S. payrolls due later in the day, while the yen was also benefiting from risk aversion.
"Widening euro zone CDS and bond spreads over German Bunds are making investors less confident, which is weighing on the euro and putting pressure on equity markets," said Jeremy Stretch, strategist at Rabobank in London.
"That is leading to the risk-aversion trade which means the dollar is in favour."
The dollar index <.DXY>, which tracks its moves against a currency basket, climbed as high as 80.435, its strongest since July 2009 as European shares <.FTEU3> fell nearly 2 percent.
The euro <EUR=> fell as low as $1.3649 according to Reuters data, its weakest since May 2009, marking a 10 percent fall from its December 2009 high around $1.5140. By 1035 GMT, it traded at $1.3680, down 0.4 percent on the day.
Ongoing fiscal concerns in the euro zone and looming U.S. payrolls have cranked up implied volatility in the currency options market, with one-week euro/dollar vols <EURSWO=> trading around 14 percent compared with 11.85 percent on Thursday.
Analysts said such a change on the day had not been seen since Lehman Brothers filed for bankruptcy in autumn 2008.
Versus the yen, the single European currency <EURJPY=R> fell to a session low of 121.99 yen, hovering in range of 121.54 yen hit on Thursday for the first time since February 2009.
The euro <EURCHF=> traded at 1.4700 Swiss francs, pulling back from a high of 1.4905 francs hit on trading platform EBS in Asian trade on suspected intervention by the SNB. Spokesmen for the central bank and the Bank of International Settlements declined comment. [ID:nWEB8427]
A fall on Wall Street on Thursday, the euro zone's sovereign debt problems and an unexpected rise in U.S. weekly jobless claims, coming just ahead of key U.S. monthly jobs data later on Friday, made for jittery markets.
A Reuters poll looked for US payrolls to come in flat on the month at 1330 GMT. [ID:nN03175623]
"There will definitely be increased sensitivity to a soft number today which would lead to more risk aversion", said Paul Robson, strategist at RBS.
He added that a weak figure may keep the euro under selling pressure, pushing it lower against the yen in particular.
This weekend's G7 meeting of central bankers and finance ministers in Canada was also in focus.
Some in the market speculated that the yuan may come under discussion due to increasing calls for the Chinese currency to appreciate, although Japan's finance minister said he did not request the yuan to be on the agenda. [ID:nLDE6140QP]
Analysts said it was unlikely that currencies would be addressed in the final communique.
"Central bankers have more to worry about than currencies at the moment, such as the withdrawal of policy stimulus, and I do not expect any reference to currencies at the G7 meeting", said RBS' Robson. (Editing by Toby Chopra)