Bill Aitken said the move amounted to policing on the cheap.

The force is advertising for eight "investigative assistants" to help gather evidence and conduct interviews.

The Conservative's justice spokesman Bill Aitken attacked the move as an inadequate alternative to new officers.

A police spokesman insisted the new assistants would help free up officers from tasks not requiring police powers.

Current advertisements for the posts specify a preference for previous investigative skills and a "high level of IT, interpersonal and communication skills".

The force is offering to pay a salary of �17,250 plus shift allowances.

Mr Aitken told the Scottish Daily Mail: "While I am all for more civilians to free up police officers, this is yet another instance of policing on the cheap.

"Kenny MacAskill needs to keep his promise of 1,000 new officers and not hide behind cheap and inadequate alternatives."

'Key objective'

The force and the Scottish Government have both defended the move.

The Liberal Democrat justice spokeswoman Margaret Smith also attacked the plan, describing it as "ludicrous".

She said: "While there is definitely a place for civilians to work with police to free up qualified officers for front line police work, there is a point at which people rightly expect criminal investigations and sensitive procedures to be carried out by fully trained police officers.

"With the SNP's u-turn on its manifesto commitment to 1000 extra police officers, I sincerely hope that this is not the shape of things to come for Scotland's police forces."

A Central Scotland Police spokesman denied hiring the assistants amounted to cheap policing.

He said: "The planned recruitment of civilian investigative assistants is being piloted as one of the measures we are progressing as part of a workforce modernisation initiative.

"The key objective of this is to free up officers from doing tasks which do not require police powers, allowing them to concentrate on tasks which do require police powers and increase their availability to communities."