AT&T may face a strike by about 40,000 employees if the phone company fails to reach an agreement with unions over issues from health-care benefits to vacation before current contracts expire this weekend.

The Communications Workers of America is renegotiating four separate contracts with the largest U.S. phone company, all of which expire at 12:01 a.m. Sunday, said Candice Johnson, a CWA spokeswoman. Last Saturday, union members voted to authorize CWA to call strikes if new contracts can’t be reached.

AT&T and the unions disagree on matters ranging from guaranteed weekend days off to wellness and health-care costs, according to the unions. CWA, which represents about 16 percent of Dallas-based AT&T’s approximately 256,000 workers, is organizing rallies and meetings to help push for a deal.

“We are working very hard to finish negotiations and get a fair contract,” Johnson said in an interview.

AT&T and main rival Verizon Communications regularly negotiate with unions representing larger parts of their workforce. About 55 percent of AT&T’s employees were represented by CWA, the International Brotherhood of Electrical Workers or other unions, according to the company’s annual report. Contracts covering approximately 120,000 employees will expire during 2012, the company said.

“As one of the largest employers in America we’re proud of the number of high-paying, middle class careers we’ve produced,” Marty Richter, an AT&T spokesman, said in an e-mail. “Our goal is to do everything in our power to protect those careers.”

— Bloomberg News

Paul Sancya

FILE - In this Jan. 25, 2007 file photo, the AT&T Michigan headquarters is shown in Detroit.