NEW DELHI, Jan 17 (Reuters) - Indian Prime Minister Narendra Modi said on Monday that a collective global effort is needed to deal with the problems posed by cryptocurrenices. "The kind of technology it is associated with, the decision taken by a single country will be insufficient to deal with its challenges. We have to have a similar mindset," Modi said at the World Economic Forum"s virtual Davos Agenda conference. India has been mulling virtual currency-related regulations which were widely expected to be introduced in the winter session of the parliament in December before being shelved. read more New Delhi has previously flagged that it plans to ban most cryptocurrencies - a move which would follow recent measures by China that intensified its crackdown on cryptocurrencies. India"s central bank has also voiced "serious concerns" around digital currencies saying that they may impact financial stability. There are an estimated 15 million to 20 million cryptocurrency investors in India, with total crypto holdings of around 400 billion rupees ($5.39 billion) according to industry estimates. India is also working on signing free trade agreements with many countries, Modi added. India recently announced a start to free trade talks with Britain with the intent of signing a deal by the end of this year. The prime minister also said that it was the best time to invest in India because the country was willing to become a more trusted partner in global supply chain. ($1 = 74.2780 Indian rupees)