TOKYO, Nov 18 (Reuters) - Bank of Japan Governor Haruhiko Kuroda said on Wednesday it was premature to discuss how to reduce the central bank’s massive holdings of exchange-traded funds (ETFs). The BOJ already buys ETFs “quite flexibly” and can reduce purchases when the market risk premium is not rising, Kuroda told parliament. “If inflation hits our 2% target and an exit from our massive stimulus programme comes into sight, there will certainly be debate on how to end our ETF buying. But it’s premature to do so at this stage,” he said. (Reporting by Leika Kihara; Editing by Chris Gallagher)