TOKYO, Nov 9 (Reuters) - The Bank of Japan must seek ways to ensure its purchases of exchange-traded funds (ETF) are sustainable as the coronavirus pandemic may force it to maintain its ultra-loose monetary policy for a prolonged period, one of its board members was quoted as saying at the bank's October rate review.

The summary of opinions at last month's meeting, released by the BOJ on Monday, also showed one member warning that prolonged crisis-mode policies could delay structural reforms needed to foster sustainable economic growth. (Reporting by Leika Kihara Editing by Chang-Ran Kim)