The survey, published yesterday by the Chartered Institute of Purchasing and Supply (CIPS) and financial information company Markit, appears to chime with the Bank of England's view that UK unemployment is likely to fall only slowly even if the country's belated economic recovery does continue.
CIPS's business activity index for services rose from 60.2 in July to 60.5 in August on a seasonally-adjusted basis, thus moving even further above the level of 50 which is calculated to separate expansion from contraction to signal the strongest monthly expansion since December 2006.
In contrast, CIPS's employment index for services dropped from 53.6 in July to 50.6 in August.
The pace of increase in new business for UK services companies accelerated to its fastest since May 1997, according to CIPS's survey, which does not include the retail industry. Strengthening client confidence was cited by services companies as a key reason for the strength of new business.
CIPS noted that, while the service sector workforce had now risen for eight consecutive months, the rise in August signalled by its survey was the weakest during this period of increase.
Detailing the situation, CIPS said: "Broadly similar numbers of companies registered a rise in employment as indicated a decline."
It added: "Where an increase in payroll numbers was signalled, panellists reported taking on staff in response to further rises in new business and associated pressure on capacity. There were a number of reports from panellists that voluntary leavers had yet to be replaced. Cost considerations were noted as a factor for any forced departures."
The weakness of employment growth signalled by CIPS's survey highlights the continuing challenges facing the UK economy, given the extent to which recent growth has been dependent on hard-pressed households.
The Bank of England's Monetary Policy Committee said last month that it did not intend to raise base rates from 0.5%, at which they have stood since March 2009, at least until the International Labour Organisation measure of unemployment, which stood at 7.8% in the three months to June, had fallen to a "threshold" of 7%. It projects this will not happen until 2016, although its forward guidance is subject to caveats on inflation and financial stability.
Martin Beck, UK economist at consultancy Capital Economics, said: "The UK economy's dominant sector appears to be roaring ahead."
However, he added: "Evidence that increased demand is being met more through higher productivity than rises in employment suggests that the momentum in the economy should not mean that interest rates rise more rapidly than the MPC currently expects."