His appearance at the committee also follows newspaper reports of a leaked document containing figures from the Police Reform Board, suggesting the force faces £300 million-worth of cuts over the next three-and-a-half years, while 550 civilian staff would be lost immediately.
Meanwhile, the committee will also hear from the Association of Chief Police Officers in Scotland, Association of Scottish Police Superintendents, the Scottish Police Federation and Unison Scotland.
Chief Superintendent David O'Connor, president of the Association of Scottish Police Superintendents, is expected to express concerns over the lack of information about the single service.
In a written submission to the committee, he said: "The uncertainty and lack of meaningful consultation on a range of proposals to date has been unhelpful, although the scale of the challenge is acknowledged. We have long argued for the early appointment of the chief constable and hope that there will now be a rapid improvement in communication and clarity over decisions that will affect my members, other staff associations and the public we serve."
On the budget, he said: "It is difficult to be optimistic when considering the financial reality we all face. My experience tells me that it is almost inevitable that the police will face the consequences of cuts in other services in terms of increased demand, perhaps not as recorded crime but in dealing with people and families in crisis. We are fortunate that, despite our imperfections, the police service has a default can-do attitude. In the context of budget cuts, it is time to question if that attitude can persist."