APRA's decision to grant a restricted banking licence to start-up deposit taker volt bank has created a conflict of interest for a long serving director of ING Bank Australia.Sydney barrister John Masters has sat on the ING board since 2010 but also joined volt bank's holding company, volt Corporation, as a foundation director last October.Now that volt bank is operating with a restricted banking licence and is moving swiftly to secure a full authority, its commercial interests are now formally opposed to those of ING Bank.That Masters could be involved in setting strategy and tactics for the banking newcomer to compete against market incumbents such as ING should be a matter of concern for the Dutch-owned bank's local chairman, Michael Katz.Masters' role as a director at both banks seems untenable and his conflict is likely to be resolved by him vacating his seat at ING.The governance benchmark in Australia seems to be that a director cannot sit on the boards of two institutions that compete for deposits.However, the prudential regulator has not intervened in cases where directors on the boards of financial institutions that compete for lending business.The classic case study has been Westpac director Peter Hawkins who concurrently retains a seat on the board of another home lender, Liberty Financial.