The Swiss National Bank said yesterday that it was keeping open all options to bring down the “massively” over-valued safe-haven franc, including pegging it to the euro as well as imposing a negative interest rate.

In separate interviews published in the Swiss national press, top Swiss central bankers signalled that further action could be taken to ease the pressure on the currency without resorting to direct intervention on the foreign exchange market.

“Nothing is excluded, I repeat,” Jean-Pierre Danthine, a member of the central bank’s governing board told Le Temps newspaper.

Asked if the SNB would peg the franc to the euro, Mr Danthine said: “It would certainly not be the easiest measure to implement, both politically and legally. “But we have a legal mandate to adopt an independent monetary policy.”

Asked the same question, Swiss National Bank vice-president Thomas J. Jordan also told newspaper Tages-Anzeiger that “basically, we can take all measures that ... is compatible with our mandate”.

“Temporary measures which control the exchange rate do fall under our mandate,” he said.

However, “we have at the moment still possibilities to expand the monetary policy further, without intervening in the currency markets.

“And we have come to the conclusion that increasing liquidity is currently the appropriate measure to take,” Mr Jordan said.

On Wednesday, the central bank took fresh measures to halt the rise of the Swiss franc by flooding the market with liquidity, after the currency reached record high levels against the dollar and the euro.

“We consider the current exchange rate against both the the euro and the dollar to be massively overvalued,” Mr Jordan said, without giving a fair value estimate.

Beyond pegging the franc to the euro, central bankers would also not rule out the possibility of imposing a negative interest rate to penalise foreign investors in the currency. While stressing that the option was on the table, Mr Danthine said however that “certain measures could have very negative secondary effects”.

“There is no magic wand,” Mr Danthine said.

Export-led Switzerland has been worried about the rise of the franc, with several Swiss firms blaming the strength of the currency for reducing earnings they were repatriating.