The Scottish Ambulance Service has defended its performance after figures showed that the number of complaints had more than doubled in three years.
Conservatives claim the rise in complaints is "worrying"
The rise from 198 complaints in 2004 to 440 last year was branded "worrying" by Tory health spokesman Jackson Carlaw.
The figures were revealed to Mr Carlaw in a series of parliamentary answers.
However, the Scottish Ambulance Service said the number of complaints last year was "normal" - while 2004 had been an unusually quiet year.
"It is 440 complaints in a year when we have helped around two million patients," he added.
Mr Carlaw said: "These deeply worrying figures pose many further questions.
"At a time when taxes have risen substantially and we are constantly told that investment in our health service stands at an all-time high, people have a right to ask why all the figures appear to be going in the wrong direction."
The figures also revealed a drop in the number of vehicles operated by the ambulance service and a fall in the number of volunteer drivers.