The Australian Border Force has been warned over illegal body searches of passengers at international airports in a report that found immigration officers routinely lacked adequate guidance about their powers.

A critical report by the Commonwealth auditor accused the Border Force of failing to "adequately address the risk of officers exercising coercive powers unlawfully or inappropriately", despite making improvements.

Immigration secretary Michael Pezzullo took aim at the "unworldly" audit office after another critical report. Credit:Andrew Meares

Immigration boss Michael Pezzullo conceded to "a number of administrative deficiencies" within his department but shot back at the National Audit Office over "loose terminology" and findings he called "unworldly".

It was the third ANAO report critical of the department's internal procedures, and found the Border Force had failed to adequately instruct and educate officers who exercise intrusive powers, such as body searches.