The loan was in the names of Sun and Lao to buy a property in Cordelia Place, Flagstaff.
In support of the loan were BNZ bankslips and statements, documents Sun had altered to misrepresent the couple's financial situation.
Sun had inflated the couple's incomes and reduced their actual mortgage balance to meet ASB's lending criteria.
However, the bank was suspicious because of dealings with him in 2010 when he failed to disclose external debt when applying for a personal loan.
As ASB investigated, Sun applied for a loan of the same amount to buy the same property through the bank where he worked, BNZ, on December 29, last year.
He provided ANZ and BNZ bank statements that had also been altered to increase the couple's incomes.
On January 4, BNZ approved the loan without realising Sun's fraud.
A week later, ANZ approved a housing loan of $288,000 and two days later another loan of $284,000 was also approved for a house and land on property now known as 11 Alker Rd, Hamilton.
Again, the documents provided to the bank by Sun were fraudulent.
It wasn't until February 3, when ASB asked BNZ to verify his bank statements that suspicions were raised.
BNZ investigated and realised the documents had been forged. It began an internal investigation of Sun, Lao and their mortgage broker. ASB declined the loan application.
By February 10, BNZ still hadn't been able to confirm who was responsible for the fraud so had to approve the couple's $1.016m loan to avoid paying heavy penalties for delayed settlement.
Four days later, the bank received another request to verify documents - this time from ANZ and again confirmed they had been forged.
The mortgage broker was cleared of any wrongdoing on February 27, and the bank determined fault lay with Sun and Lao.
A disciplinary meeting was held on March 8 when Sun admitted falsifying documents without his wife's knowledge.
An examination of his personal email revealed the fraudulent documents had been sent to BNZ from that address.
The home loans for the Cordelia Place property were transferred to SBS Bank in May. When contacted by police the bank carried out an internal investigation and was satisfied the documents were not fraudulent.
However, they declined to provide details of their lending to police.
A search of the property on Quotable Value's website reveals the couple paid $1,180,000 on May 4. They remain in the house.
Sun was remanded on bail and will reappear for sentencing next month.