The Australian police has widened its investigation into alleged drug trafficking ring operation involving some personnel of Australia's fourth largest bank, Australia and New Zealand Banking Group (ANZ).

State media said that the police believed that ANZ's internal email system has been compromised by a group of ANZ employees who were running a drug trafficking operation within the bank's office.

A spokesman for the bank said the company was cooperating with investigators and is trying to determine if the reports are true.

"We have been completely shocked by the situation and everyone at ANZ is incredibly disappointed by the matters the police are looking into," the spokesman told Reuters.

The unnamed spokesman said ANZ has zero tolerance for such criminal activity and added all of those allegedly involved in the operations were no longer employed with the bank.

Several local media, including the Australian Broadcasting Corp., reported that ANZ's internal email system had been used by "some employees" to traffic drugs.

The Australian Federal Police said it had arrested a 30-year-old man in connection with probe. The unidentified suspect was charged for allegedly importing a drug called 4MMC, known in the streets as "meow meow." A spokeswomen for the police did not provide other details pending investigation into the matter.

But the Herald Sun reported that least seven ANZ staff are being investigation for their alleged involvement in selling the said drugs. Another seven are believed to have bought the drugs from them.

Some 14 ANZ staff have been dismissed for improper use of the company's email system, the report said.