Another high-ranking member of the Australian Border Force (ABF) has taken "extended leave" as his personal conduct is examined, the ABC can reveal.

The revelation comes on the same week it was confirmed Australia's Border Force commissioner, Roman Quaedvlieg, has gone on leave amid an external investigation.

The Immigration Department is refusing to officially confirm if a review has been launched into the behaviour of the second senior uniformed ABF officer, who is currently not at work.

"The department does not comment or confirm whether any matter is, or is not, under investigation," the Department of Immigration and Border Protection said in a statement.

Several specific questions concerning the officer were submitted to the Department by the ABC, but were not answered.

"The department has a robust integrity regime which has been the subject of numerous public statements, including on our website," the department told the ABC.

"The Secretary has also addressed this [integrity] issue in opening statements at Senate Estimates."

Australian Border Force Commissioner Roman Quaedvlieg with Immigration Minister Peter Dutton. ( ABC News: Avani Dias )

The Australian Border Force commenced operations in 2015 and Mr Quaedvlieg is its inaugural commissioner.

Commissioner Quaedvlieg is a career police officer and was previously the chief police officer of ACT Policing — an arm of the Australian Federal Police.

The Acting Immigration Minister Michael Keenan released a short statement on July 2nd confirming Mr Quaedvlieg's extended leave.

The department has not outlined any of the specifics of the case.