The Swiss National Bank said on Wednesday it would expand existing measures to counter the runaway Swiss franc by expanding bank sight deposits and that it would take further measures against the currency's strength if necessary.

The measures taken thus far by the Swiss National Bank (SNB) against the strength of the Swiss franc are having an impact. Nevertheless, the Swiss franc remains massively overvalued, the SNB said in a statement.

It said it would expand banks sight deposits to 200 billion francs from 120 billion francs. To achieve the new target level the SNB said it would repurchase outstanding SNB Bills and employ foreign exchange swaps.

The SNB has already slashed interest rates to zero and last week said it would use forex swaps to accelerate the increase in Swiss franc liquidity.

(Reporting by Caroline Copley)