The number of police officers only able to perform restricted duties has almost trebled in five years, figures suggest.

There were 1,412 officers not able to perform all aspects of their job in 2011-12, according to statistics released under freedom of information law.

That compares with 560 in 2006-07 and means that around one in 12 police officers (8%) were on restricted duties last year.

In the Central and Tayside areas, one in seven officers (14%) were on restricted duties in 2011-12, compared with just one in every 33 (3%) in Northern Constabulary

Police can be put on restricted duties because of injury, illness or pregnancy.

Former Tory leader Annabel Goldie criticised the number of officers who have gone from "the frontline to behind a desk".

The Conservatives "forced the SNP in 2008 to deliver 1,000 extra police officers", she said.

"What good is that when there has been such an increase in those placed on restricted duties?

"This rise will have had a dramatic impact on Scotland and the public will want to know why this trend has developed.

"With the creation of a single police force for Scotland just around the corner, the SNP must do all it can to ensure we get this figure back down, otherwise public safety will be put at risk."

Miss Goldie pressed Justice Secretary Kenny MacAskill on the issue in Holyrood.

Mr MacAskill said the number of officers on restricted duties is "fundamentally" a matter for the police.

"What I can say is that police officers tend to be on restricted duties for a variety of circumstances, for example pregnancy, and as we have an increase in the number of female officers, that's a factor that has to be taken into consideration," he told MSPs.

"Equally, officers who have suffered injuries, and tragically too many officers do suffer injuries in the course of their duties, also have to be protected.

"We currently have a record number of police officers in Scotland, which contributed to safer and stronger communities with recorded crime at a 37-year low."