A former NSW bank employee is facing a raft of charges over an attempted fraud against the National Australia Bank valued at more than $21 million.

Detectives from the State Crime Command’s Financial Crimes Squad uncovered fraudulent bank deposit guarantees had been used to buy properties across the state, for an inflated commission.

On August 6 officers searched a western Sydney home at Fairfield East, seizing electronic devices and documentation including internal NAB vouchers.

Financial Crimes Squad detectives later charged a 47-year-old man with 11 fraud offences.

It will be alleged in court he was involved in attempting to defraud NAB of more than $16.8 million.

He was granted bail to appear at the Downing Centre Local Court on Wednesday.

Investigators then arrested a 38-year-old woman in Newtown on October 8.

The woman, who is a former bank employee, was charged with nine fraud offences and participation in a criminal group activity.

Police allege the woman was involved in attempting to defraud NAB of more than $21.6 million.

She was granted conditional bail to appear at Downing Centre Local Court on November 27.

NAB Executive Group Investigations and Fraud Chris Sheehan said the bank referred the matter to the authorities as soon as its systems detected unusual activity.

“It is important to note no NAB customers were impacted and no financial loss occurred as a result of the actions alleged by police, and the former employee was dismissed by NAB.”