A former National Australia Bank and Commonwealth Bank employee and his mortgage broker wife have been arrested and charged with facilitating more than A$40 million worth of fraud for a financial crime syndicate accused of fleecing Australia’s major banks of hundreds of millions of dollars.

Huy Tin Nguyen, 34, and his wife, Thu Huong Nguyen, 35, are accused of helping the Penthouse Syndicate – alleged to be one of the biggest fraud and money laundering syndicates in Australian history – build a luxury property empire across Sydney and defraud the country’s finance giants with the help of a network of corrupt bankers, mortgage brokers, solicitors, real estate agents and property developers.

The pair was arrested at their Wentworth Point home on Tuesday morning by financial crimes squad detectives working under Strike Force Myddleton.

Their arrests mark the latest milestone in the unravelling of the Penthouse Syndicate, which the Sydney Morning Herald previously revealed was accused of defrauding NAB of more than A$150 million using corrupted insiders on its payroll.

Several NAB employees suspected of receiving bribes to knowingly approve fraudulent loans have been sacked and remain under investigation.