"It is suspected that there is a substantial amount that is still yet to be discovered, which is most likely to have been fraudulently obtained," said Watt.
He said police would allege the woman had processed "a large number of separate transactions" to steal the money.
He said customers were being contacted though money was only stolen from the company.
The woman declined to be interviewed by police and was released on bail. She is to appear in Queenstown District Court tomorrow.