The survey results throw further doubt on Scottish Government claims that the jobs market north of the Border is outperforming the rest of the country.
At 62.5 in April, down from March's 63.9, the Bank of Scotland Labour Market Barometer - a composite indicator designed to provide a single figure snapshot of labour market conditions - remained well above the 50-point level that signals improvement, indicating that Scotland's job market is making substantial progress.
But the barometer was lower than its UK equivalent for the first time in 14 months and in the case of permanent positions the Scottish labour market underperformed the wider UK for the fourth consecutive month.
Permanent placements in Scotland rose for the 19th time in the past 20 months in April, although the rate of increase dropped sharply to the weakest since May 2013 while the UK as a whole accelerated.
The Bank of Scotland put the blame for a slowing in appointments on a lack of candidates.
Donald MacRae, chief economist at Bank of Scotland, said: "The Scottish labour market continued to improve in April. Demand for staff was strong but accompanied by a lack of available candidates. As a result the number of people appointed to permanent jobs rose but at a slower rate than in recent months."
He added: "Salary inflation picked up in the month partially reflecting demand for staff."
Official figures published last week showed that the number of Scots in work reached 2,585,000 in the January to March period.
The Scottish Government said those figures showed the success of its investment programme while sceptics pointed to the rising number of older workers and said the Scottish labour market has yet to catch up with the rest of the UK after being hit harder during the recession.
The Bank of Scotland found that permanent appointments rose the fastest in Glasgow last month with only Aberdeen recording a reduction in placements.
Growth in temporary billings in Edinburgh and Dundee was offset by contractions in both Aberdeen and Glasgow.
Aberdeen saw the most marked deteriorations in both permanent and temporary staff availability.
Glasgow led the way in increases in both permanent starting salaries and rates of pay for temporary staff.
Across Scotland as a whole, April saw permanent starting salaries rise sharply, and at a faster rate than in the previous month.
Growth in hourly pay for temporary staff eased to a three-month low, but remained solid.