WASHINGTON (Reuters) - U.S. private payrolls increased far less than expected in July, but that likely is not a true reflection of a labor market that continues to moderate gradually.

Private payrolls rose by 122,000 jobs this month after advancing by an upwardly revised 155,000 in June, the ADP National Employment Report showed on Wednesday. Economists polled by Reuters had forecast private employment would increase by 150,000 positions after a previously reported gain of 150,000.

The ADP report, jointly developed with the Stanford Digital Economy Lab, was published ahead of Friday's more comprehensive and closely watched employment report for July from the Labor Department's Bureau of Labor Statistics. Initial prints have largely understated private payroll growth so far this year.

Economists polled by Reuters expect the BLS data to show 148,000 jobs were created in the private sector in July, up from the 136,000 added in June. Total payrolls are estimated to have increased by 175,000 jobs compared to 206,000 in June. The unemployment rate is forecast to be unchanged at 4.1%.