The franc has traded almost in tandem with the euro since it was capped at 1.20 francs per euro by the Swiss National Bank on Sept. 6 after safe-haven buyers nearly pushed it to parity, threatening to tip the Alpine economy into recession.

Selling pressure on the euro has intensified this week on signs contagion was spreading to Spain and even France, and the single currency is on track for its biggest one-week drop since early September.

"The broader market stays obsessed with all things euro zone crisis," said Informa Global Markets analyst Tony Nyman. "If bond yields continue to soar, especially if the Spanish 10-year rises above 7 percent, expect dollar/Swiss to continue higher by default towards 0.9250 again."

Yields above 7 percent are seen as unsustainable for developed market governments. Spain on Thursday had to pay the highest rate to sell its 10-year debt since 1997, just shy of the 7 percent mark.

Signs are also mounting the Swiss economy is set for a slowdown, with economists at bank Julius Baer forecasting a recession in the first half of 2012.

The ZEW index of economic expectations fell in November, with a clear majority of financial market experts surveyed foreseeing a deterioration of economic conditions in Switzerland over a six-month horizon.

"The weakening economic outlook has raised expectations for further easing by the SNB," analysts at Credit Suisse said. "This could keep the franc on a weak footing against the dollar, with the October high of 0.9316 being the next key resistance area."

The franc rose 0.7 percent against the dollar compared to the New York close to trade at 0.9157 by 0755 GMT.

The franc rose 0.2 percent against the euro to 0.2382 francs per euro.