SYDNEY, March 5 (Reuters) - A former senior executive of...

SYDNEY, March 5 (Reuters) - A former senior executive of National Australia Bank Ltd (NAB) was arrested on Tuesday on suspicion of involvement in an operation to charge A$40 million ($28 million) of fraudulent contracts to the bank, Australian media reported.

Rosemary Rogers, former chief of staff to NAB's chief executive officer, presented herself to New South Wales (NSW) state police in Sydney and was arrested, said the Sydney Morning Herald newspaper.

NSW police said in a statement that a 43-year-old woman had travelled to a police station in relation to "allegations of corrupt commissions being paid for contracts with a financial institution", without naming the woman or the company.

"The woman, who is a former executive employee of the financial institution, will be charged later today," the statement said.

NAB, Australia's fourth-largest bank, declined to comment on Tuesday and referred Reuters to a statement it released last week which said that "if the alleged fraud is proven, it represents a most serious breach of trust by a former employee".

Australian police first reported they were investigating allegations of fraud at NAB last April, including raids on properties. A second 43-year-old woman was charged over the investigation four days ago, police said.

($1 = 1.4114 Australian dollars)