The deputy prime minister told Sky News on Thursday that he looks forward to dealing with the allegations “fully and transparently”.
It comes after the BBC reported that civil servants who worked for Mr Raab are preparing to file formal bullying complaints.
Rishi Sunak has appointed senior lawyer Adam Tolley KC to investigate two formal complaints made last week over Mr Raab’s behaviour, but No 10 says the prime minister still has full confidence in him.
And Mr Raab also insisted it was “entirely legitimate” and in line with guidance to use his personal mobile for some work matters, after Newsnight reported allegations he used his personal email for government business at two different departments.
Asked by Sky News whether he had been told that more senior officials who worked closely with him had submitted complaints, Mr Raab replied: “I have behaved professionally at all times.
“And I am the one that when the complaint came in a matter of days ago, the first that had ever come against me since I have been a minister since 2015, called for an independent inquiry and I look forward to dealing with it fully and transparently rather than dealing with anonymous comments in the media.”
Asked about allegations surrounding his mobile phone, he replied: “I have always adhered to the ministerial code, including the use of my iPhone.”
He said he had “always been careful to protect the integrity of any communications” he has.
Asked how this does not constitute breaching the ministerial code, the deputy prime minister replied: “It is very clear, I took advice on it. I am confident in that.”
Probed on reports that senior civil servants had told him not to use his personal phone for government business, Mr Raab dismissed the claims as “anonymous speculation”.
He added that he had “always taken advice” on how to protect the integrity of communications and, when asked why he used his personal phone for some things, replied that it was “entirely legitimate and in line with the guidance that we have”.
“I haven’t broken the ministerial code, I am confident, in any of the ways you are asserting,” Mr Raab said.
He had previously told MPs he would “engage thoroughly” with the investigation into him and looked forward to “transparently addressing” the complaints.