The First Minister used a radio interview to stress an independent Scotland could not be prevented from using sterling. Asked what his Plan B was, in the event the UK Government maintained its opposition to the First Minister's proposed currency union, he said: "Of course the pound is an internationally tradable currency.
"It's not a question of keeping the pound, it's a question of whether there would be agreed a currency union."
Chancellor George Osborne, his opposite number in Labour, and the LibDems have all said the UK would not agree a formal deal to share the pound because it would be too risky.
Mr Salmond insists they are bluffing, claiming the currency union would be in the interests of both countries.
His comments sparked fresh calls to spell out his Plan B from the head of the pro-UK Better Together campaign, Alistair Darling. He dubbed sterlingisation, or keeping the pound without a formal deal with the rest of the UK as "the Panama Plan" in a reference to Panama's use of the US dollar.
The former chancellor said: "It's quite clear that a currency union is off the table. Alex Salmond needs to tell us what will replace the Pound.
"Adopting the Panama Plan, which is rejected by his own Fiscal Commission, would leave Scotland with no financial back-up."
The First Minister's official spokesman said Mr Salmond's comments were "no more or less than a statement of fact".