RNZ reports the acting police commissioner, Afamasaga Michael Soonalole, said the two suspects and one other man, all of them Chinese, arrived in Samoa from Fiji early this month and stayed in a local motel.
One of the trio has left the country.
The acting commissioner said the alleged theft was discovered after the bank viewed surveillance footage of people using the ATM machines at night.
He said the suspects used a machine to produce cards enabling them to access pin numbers and get out cash.