Rishi Sunak has declined to say whether he will sack Dominic Raab if an inquiry finds that he bullied officials.
The Justice Secretary has pledged to resign if he is found to have bullied staff.
The investigation by lawyer Adam Tolley KC is expected to be drawing to a close after the Cabinet minister himself was interviewed.
Dozens of officials are thought to be involved in eight formal complaints.
“I’m not going to pre-empt a process that hasn’t concluded,” Mr Sunak told BBC Breakfast.
“People can judge me by my actions. In the past when there’s been issues like this, I’ve made sure that they were investigated properly.
“I was the one who initiated this investigation. I was the one who appointed a leading independent KC to get to the bottom of it.”