* Cryptocurrencies don't have assets to back up value - Kuroda
* Adds cryptocurrency mostly used for speculative trading
* G20 to debate cryptocurrency impact in March (Adds quotes, detail)
TOKYO, Feb 13 (Reuters) - Bank of Japan Governor Haruhiko Kuroda said on Tuesday cryptocurrencies likely won't threaten legal tenders like the yen any time soon as they are mostly used for speculative trading, rather than as payments and settlement means.
Kuroda also said the BOJ was closely watching developments in cryptocurrrency trading to ensure they do not erode public trust over the safety of existing settlement systems overseen by the central bank.
"Cryptocurrencies aren't legal tenders and don't have assets to back up their value," Kuroda told parliament, adding that the prospect of them threatening the role of globally-trusted legal tenders such as the yen was low.
"Some people say they should be described as crypto-assets, not cryptocurrencies," he said.
Kuroda's comments came in the wake of recent calls from global policymakers for a coordinated approach to regulating cyptocurrencies like bitcoin, which has drawn attention due to its highly volatile moves and increasing trading volume.
Finance leaders from the Group of 20 major economies are expected to discuss the impact of cryptocurrencies at their meeting in Buenos Aires in March. (Reporting by Leika Kihara; Editing by Chris Gallagher Editing by Shri Navaratnam)