Qwest Communications International, the No. 4 American local telephone carrier, and a union resumed talks yesterday, the union said.

The talks on contracts for 25,000 of the company’s workers, which were suspended earlier yesterday, started again at 6 p.m. Denver, Colo., time, the Communications Workers of America said in an e-mailed statement. The existing contracts expired at 12:01 a.m. The two sides had expected talks to resume.

A CWA spokeswoman, Candice Johnson, wouldn’t comment beyond the statement.

Qwest negotiators, in talks since June 22 over contracts for 60% of the company’s workforce, failed to reach an agreement before the deadline, though averted a walkout for now.

The company and CWA locked horns over wages, health-care costs and mandatory overtime, the union has said.

The union is pushing for a salary increase for workers whose wages haven’t budged in more than two years. CWA leadership yesterday approved a strike and said negotiations were “disappointing.”

“CWA members at Qwest have endured a wage freeze for three years, and have made sacrifices to help keep Qwest in business over a rocky period,” the CWA said in Saturday’s statement.

Shares of Denver-based Qwest fell 12 cents to $3.88 on Friday in New York Stock Exchange composite trading. They’ve declined 13% this year.

Qwest and larger American telephone companies including Verizon Communications and SBC Communications have big portions of their employee bases represented by unions. Every few years, the companies must work out new contract terms, striving to keep costs in check while at the same time avoiding walkouts.

SBC Communications, the second largest American local phone company, last year reached an agreement with the CWA after a four-day strike. San Antonio-based SBC was forced to accept limits on its ability to fire union represented workers, while employees were asked to pay more of their healthcare costs.

The CWA said on Thursday that it is resisting a push by Qwest to get employees to work more overtime and bear a bigger share of their health care expenses. Disagreements over overtime erupted in a strike at a predecessor company in 1998.

“It doesn’t sound like the union is going to cave on this overtime issue,” a Janco Partners analyst, Donna Jaegers, said. Ms. Jaegers, who rates the shares “neutral,” spoke in an interview Friday.

Qwest proposed doubling the number of overtime hours an employee could be forced to work in a given week, increasing the tally to 16 from eight, the CWA has said.

Employees on August 5 gave the union authority to call a strike in the event an agreement isn’t reached on time. The CWA president would have to set a date for a strike to occur.

The chief executive of Qwest, Richard Notebaert, who this year lost out to no.1 carrier Verizon Communications in a bid to buy MCI, is racing to stem losses as local phone clients switch to cable and wireless competitors. The company has suffered losses in four of the last five years.

Each month of a strike could shave a percentage point of the company’s gross margin, or the percentage of sales after subtracting the cost of goods sold, an analyst at Des Moines, Iowa-based Principal Global Investors, Tim Gilbert , said. Principal manages $143 billion in assets and owns 1.03 million Qwest shares.

Sales rose for the first time in four years last quarter as Qwest reduced operating expenses 15% after abandoning a bid for MCI, the no. 2 American long-distance company. Mr. Notebaert is focusing on adding users of high-speed Internet access and long-distance calling to compensate for line losses.

The CWA represents Qwest employees in 13 states, including Colorado and Arizona. Qwest is the dominant local telephone provider in 14 states.