Americans could soon be allowed to make political campaign contributions in bitcoins, the Federal Election Commission has hinted.

In a draft opinion responding to a request from the Conservative Action Fund, FEC lawyers say that bitcoins can be accepted as "in-kind" contributions but that they have to be converted to dollars before they can be used.

The FEC says that bitcoin does not meet its definition of money because it is not a national currency nor a negotiable instrument like a cheque and because it does not represent a "fixed amount of money".

However, the Commission says that there is nothing in its rules that stops the acceptance of bitcoin as "in-kind" contributions along the lines of stocks and commodities.

Members of the public can now comment on the draft opinion until 13 November ahead of a Commission vote on the matter.

Senator Tom Carper took to Facebook to welcome the draft, saying: "I applaud the FEC for acting quickly to recognize this and develop a thoughtful policy that gives donors and committees rules of the road to utilise this emerging technology."

Carper chairs the Senate Committee on Homeland Security which is preparing to hold a hearing on virtual currencies in the next few weeks.

"Virtual currencies are not going away. Their emergence has potentially far reaching implications for the federal government and society as a whole," he says. "I expect this decision and other recent developments will be discussed at our Committee's upcoming hearing, as we dig into what a whole-government approach to this new and unique technology may look like."