The Immigration Department will undertake external performance reviews ahead of its merger with the Australian Customs and Border Protection Service.

Immigration Department secretary Michael Pezzullo says he will subject more than 2500 mid-level public servants to reviews, raising concern that it could lead to jobs being lost.

Tender documents have been released which call for an external contractor to undertake “individual capability assessments” of all of the department's executive level 1 (EL1) and executive level 2 (EL2) staff – about 2570 people all up

“The department is seeking to engage an external service provider to deliver the services. The services will focus on the assessment of individual capabilities,” the tender states.

“The executive level review aims to ... establish a professional, flexible, adaptable and efficient [executive level] that will enable a successful transition to the new portfolio.”

Staff are expected to undergo confidential interviews, behavioural testing and other “capability assessments” as part of the reviews.

The Immigration Department will not say whether the review will lead to redundancies.

“The review will validate the strengths and capabilities of the department's executive officers, enabling them to understand where their skills and capabilities sit against the expectations of the department,” the department told reporters this week.

The review likely relates to a previous audit report which found that the Immigration and Border Security departments had too many middle managers, leading to one in five EL2s in Immigration and almost one in six EL2s in Customs not having to oversee any staff.

The earlier report said mid-level executives were “proficient technical managers”, but possessed “patchy” core management skills.

Mr Pezzullo says he will act on all significant findings.

“In the new organisation we are creating, we will increase the span of control of the executive-level cohort and redesign accountabilities to empower our EL2 officers and staff,” he told reporters.

Budget documents predict the merger of Immigration and Customs into the new Australian Border Force will cost about $480 million and about 480 jobs from the two agencies.

When it is over, remaining staff will choose from career “streams”, which could see them attend the planned Australian Border Force (ABF) College.

New ABF officers will have more powers than current Customs or Immigration officials, including the power to detain offenders, carry guns, and gather intelligence.