TOKYO, Dec 7 (Reuters) - Japan"s top currency official Masato Kanda said on Tuesday digital cross-border payment technology would boost regional growth, but regulations and preventing financial crisis may become difficult. Speaking at an event hosted by ASEAN+3 Macroeconomic Research Office (AMRO), Kanda, vice finance minister for international affairs, said that with digitalization of payments, regulations on capital movement and currency exchange may become difficult. "Financial crisis in one country may spread faster with wider collateral effects on other countries in the region," he said.