Eugene Tsai, head of the central bank's foreign exchange department, told Reuters that transactions made by the banks in accordance with the rules before Friday had been completed on schedule.
The Taiwan dollar is at a more than 23-year-high against the greenback as the island's trade-dependent economy booms on the back of global demand for its tech products.
The suspension will be a year or more for the most serious cases, the sources said, without saying the length of time being applied to each bank.
"UBS takes note of the decision of the Dutch court to order the public prosecutor to open an investigation of Ralph Hamers, in his capacity as the former CEO of ING.