Labor senator Sam Dastyari has warned Australian banks not to "act like a bunch of ostriches" with their "heads in the sand" when confronting the rise of bitcoins, as he urged ­companies to provide feedback to a ­Senate inquiry into how to regulate the highly volatile digital currency.

National Australia Bank, Westpac Banking Corp, ANZ Banking Group and Commonwealth Bank of Australia number among 74 organisations that have been approached by the inquiry's committee, which is chaired by Senator Dastyari.

Australian banks have been highly sceptical and cautious in dealing with bitcoins. Earlier this year, NAB retreated from digital currencies including bitcoin, arguing they were too risky. Credit:Bloomberg

The list of companies, which was seen by Fairfax Media, also included the Reserve Bank of Australia, the Australian Federal Police, and international firms such as lobby group Bitcoin Foundation in the United States, and online payments behemoth PayPal.

"The fact is the banking sector can't act like a bunch of ostriches and stick their heads in the sand and ­pretend these digital currencies aren't a real thing that's heading their way – it is," Senator Dastyari told the ­Financial Review.