By Steve Gorman

LOS ANGELES (Reuters) -The labor coalition that staged a 72-hour strike by 75,000 healthcare workers against Kaiser Permanente last week is giving the company nearly three more weeks to reach a contract deal before facing a second, potentially longer walkout next month.

The Coalition of Kaiser Permanente Unions said on Monday it has served the company notice that a weeklong "follow-up strike is possible" starting Nov. 1 unless the two sides come to a settlement beforehand.

The company did not have an immediate response to the unions' latest strike deadline.

The dispute has focused on workers' demands for better pay and measures to ease chronic staffing shortages and high turnover that union officials say has undermined patient care at Kaiser, a leading nonprofit hospital network and managed-care organization.

Union and Kaiser negotiators are due to return to the bargaining table on Thursday, eight days after their last round of contract talks broke off, despite mediation efforts of Julie Su, the acting U.S. labor secretary.

Su plans to travel to California again this week for the resumption of negotiations, seeking to broker a deal, her office said.

Last week's stalemate came as more than 75,000 nurses, medical technicians and support staff took to picket lines at hundreds of Kaiser hospitals and clinics in California, Oregon, Washington state, Colorado, Virginia and the District of Columbia.

The strike, which ran for three days, marked the largest work stoppage to date in the healthcare sector. Kaiser said it kept its hospitals and emergency departments open during the walkout, staffed by doctors, managers and "contingency workers."

The company has acknowledged staffing shortages plaguing the entire healthcare sector, a consequence of occupational "burnout" from the COVID-19 pandemic, leading to more than 5 million medical workers leaving their jobs.

The unions say Kaiser's outsourcing of healthcare duties to third-party vendors and subcontactors has also emerged as a major sticking point in talks that have dragged on for six months. The workers' last contract expired on Sept. 30.

The clash has put Kaiser at the forefront of growing labor unrest in the healthcare industry - and across the U.S. economy - driven by the erosion of workers' earning power from inflation and pandemic-related disruptions in the workforce.

The deadline set by unions for their threatened follow-up strike coincides with the expiration of a contract covering another 3,000 Kaiser healthcare workers in the Seattle area, which would add them to the ranks of a second walkout if one occurs, the coalition said.

The strike would begin at 6 a.m. local time on Nov. 1 and continue until 6 a.m. on Nov. 8, the union said.

(Reporting and writing by Steve Gorman in Los AngelesAdditional reporting by Sriparna Roy in BengaluruEditing by Caroline Humer, Shinjini Ganguli and Matthew Lewis)