Vic Emery of the Scottish Police Authority was yesterday announced as the new head of Zero Waste Scotland - an environment group trying to cut landfill dumping - despite ongoing opposition criticism of the way the force is made accountable.
Labour justice spokesman Graeme Pearson, a former senior officer, said he believed Mr Emery's post should be full-time.
Mr Pearson said: "Considering the widespread reforms taking place in Scottish policing, I see the chair of the Scottish Police Authority as a full-time position which requires an appropriate commitment.
"I was therefore surprised to hear that Mr Emery is taking up a second job and hope that his new position will not detract from his role at the SPA, which ought to remain his priority."
A spokeswoman for the Scottish Police Authority, however, insisted Mr Emery, a former shipyard executive, had more than enough time to do both jobs, which are both part-time. She said: "Vic Emery is contracted to the Scottish Police Authority for 15 days a month.
"It is not and never has been a full-time appointment as he is backed up by a team of 11 other board members plus the executive management team at the Scottish Police Authority. As such, we do not anticipate any clash of availability."
A spokesman for the Scottish Government said: "Vic Emery's appointment as chairman of Zero Waste Scotland requires a commitment of two days per month. This will have no impact on his ability to discharge his role as chair of the Scottish Police Authority."
The meetings timetable allowed him to schedule his commitments.