Singapore employers expanded payrolls at a slower pace than initially estimated as the completion of some building projects prompted construction companies to hold back from adding new workers.

The city state added 20,500 jobs in the three months through September, compared with an earlier forecast of 24,100, the Ministry of Manpower said in a statement today. The seasonally adjusted unemployment rate was 2.1%.

Singapore’s services industry is still expanding even after weakening overseas demand for manufactured goods caused the economy to contract last quarter. The city’s two casino resorts run by Genting Singapore Plc and Las Vegas Sands Corp. have attracted millions to its gaming centers, helping boost spending at malls and restaurants.

“Employment growth has eased after robust gains earlier in the year,” the Ministry of Manpower said today. “Construction employment was flat after slight gains in the second quarter, due to the completion of several large building projects such as the integrated resorts and fewer new projects coming on stream.”

The services industry added 21,300 jobs last quarter, the report showed. The manufacturing industry cut 700 jobs. A total of 82,000 jobs have been created in the first nine months of 2010.

There were 50,200 job vacancies as of September, according to today’s report. Average wages before adjusting for inflation rose 5.4% in the third quarter from a year earlier.

Singapore’s unemployment rate may remain at 2.1% through the end of 2010, and fall to 2% by the end of 2011, according to the median estimate in a survey of 22 economists by the Monetary Authority of Singapore released last week.