The yen and Swiss franc rose on Friday as oil prices slid and bank shares led global equity markets lower, stoking a fresh wave of bids for low-risk assets.
Jitters about the June 23 referendum on Britain's membership in the European Union intensified the scramble for safe-haven investments, analysts said.
A poll by ORB for The Independent paper published on Friday showed the "Leave" camp had a 10-point lead over "Remain."
"The closer we get to the 'Brexit' vote, the more people will put on cautious positions," said Alan Ruskin, global head of FX strategy at Deutsche Bank in New York.
The Swiss franc reached an eight-week peak against the euro at 1.0845 francs per euro. It was last up 0.5 percent at 1.0852 francs.