The report by HM Inspectorate of Constabulary in Scotland (HMICS) found probationary officers from elsewhere in the country are being dispatched to the north-east to cover the shortfall, with many of them unable to afford to live in Aberdeen itself.
The watchdog said the Aberdeen city division had lost experienced officers to the oil and gas industry and was struggling to recruit locally.
The division is also dealing with a high number of transfer requests from officers who say the cannot afford to live in Aberdeen or the surrounding area.
But Police Scotland said the number of those leaving the force had slowed in recent months as a result of the falling oil price and the downturn in the north-east jobs market.
The HMICS report said: “Perhaps the most significant challenges facing Aberdeen City Division relate to the recruitment and retention of staff.
“Faced with a buoyant local economy and lucrative opportunities in the oil and gas industry, combined with changes to their terms and conditions, several experienced officers have left the police service.”
HMICS said that 78 per cent of officers who left Police Scotland in Aberdeen during 2014 had done so before reaching pensionable age, compared with 52 per cent for the north of the country as a whole.
It said the Aberdeen division had been working with a high proportion of vacancies until recently, which had been filled with probationers.
“Until recently, the division operated with a high proportion of vacancies. Police Scotland has sought to fill the vacancies in Aberdeen by allocating probationers to the division,” the report said.
“The division is therefore comparatively inexperienced. Some officers we spoke to during our inspection felt that this lack of experience had an impact on service delivery and they were particularly concerned at the loss of experienced officers to support and mentor probationers.”
Chief Superintendent Adrian Watson said the force had introduced a tutor unit to help probationers and had worked with local partners to make affordable housing available within Aberdeen.
Asked about the number of officers leaving, he said: “If anything, we’ve seen that tail off. That might be due to market forces, the falling price of oil - that does have an effect.
“This is an issue not just for Police Scotland. We’re having a real issue trying to get people into the public sector or third sector and keep them there (in Aberdeen).
“Of course we are a young workforce in comparison to other divisions, but it’s a handful of people who have left the organisation.”