NEW YORK (Reuters) - Call them Obamacare's army. From the chief actuary at the California health insurance exchange that President Barack Obama's healthcare reform law established to the legions of call center staffers who will help people trying to buy insurance through such state exchanges, the number of people working to implement "Obamacare" has reached the tens of thousands, a Reuters analysis has found. No one said that overhauling healthcare, which accounts for 17 percent of all national spending, was going to happen with a skeleton crew. State offices that will run insurance exchanges are hiring tens of thousands, either on staff or through outsourcing firms. Federal agencies that are key to implementing the law, such as the Internal Revenue Service, plan to hire thousands more, and private non-profit groups backed by the White House are dispatching thousands of newly hired staffers and volunteers into the field. The number of such workers, obtained through documents and interviews with officials, consultants and contractors, could be significant enough to produce a modest, if temporary, boost to employment across several industries. But the precise size of this workforce is shrouded in secrecy. The Department of Health and Human Services (HHS) did not reply to a question asking how many people it has hired or assigned to implement healthcare reform, and companies with government contracts worth tens of millions of dollars are similarly tight-lipped. HHS spent $394 million through last March on contracts to set up state insurance exchanges it will run, according to a report this week by the Government Accountability office, the investigative arm of Congress. Among them: an $88 million contract with CGI Federal Inc. for information technology work and a $55 million contract with Quality Software Services Inc. (QSSI) to build a "data hub" that will allow people to buy insurance on the state exchanges that are the heart of Obamacare. But "we do not have information on the number of people involved to implement it," said John Dicken, GAO's director of healthcare. Asked how many people its grant supported, QSSI Vice-President Mark Labus said, "That's not information I'm authorized to release." What is clear is that relatively few of the Obamacare-related jobs are in healthcare, at least so far. The sector added an average of 24,000 jobs per month over the last year, the Bureau of Labor Statistics reported this month. Helping the uninsured buy coverage is expected to bring millions more paying patients to doctors, clinics and hospitals starting in 2014, but most providers have adopted a wait-and-see attitude on staffing. Advertising and marketing teams, however, have been working for years. Porter Novelli, a public-relations giant, received nearly $10 million from HHS to help implement Obamacare, government records show - though it declined to reveal the number of workers on the project. "We do not disclose head counts of any sort," said Catherine Sullivan, director of communications. Another reason for the uncertainty about head counts is that states are only now figuring out what kind of staffers they'll need - like the marketing director California is trying to hire or the executive who will "ensure cross team alignment and work efficiency" that Oregon wants. To succeed, Obamacare must reduce the number of uninsured Americans and make affordable policies available to them, neither of which will happen unless millions of people buy coverage on the exchanges. Experts say at least 2.7 million younger, healthier people need to sign up to make the exchanges work financially. The trick is reaching and persuading them. One group that hopes to do so is Enroll America, a non-profit with close ties to the White House. It had eight staffers last year, 50 now, and is aiming for 200 this summer. It will deploy thousands of volunteers to states such as Ohio, Florida and New Jersey, where Republican leaders rejected Obamacare. For states running their own exchanges, the numbers vary dramatically. Rhode Island has nine staffers, Nevada will have 12 next month, Hawaii has 43 and Oregon has 141. But Covered California, that state's new insurance marketplace, expects to have 398, from Executive Director Peter Lee to a chief actuary and director of marketing. The big numbers are not in the central office, however, but in the field. Covered California will have 20,000 people helping the nearly 10 million uninsured sign up for coverage, said spokeswoman Anne Gonzales. It also expects to hire 500 agents for a call center in Rancho Cordova, several hundred in Fresno and up to 200 in Contra Costa, people from many walks of life, including some who have been jobless for months and who will receive intense training. Figuring out how many people are needed to enroll, say, 1,000 of the uninsured and field calls from those who are flummoxed by the online marketplaces is as much art as science, said Bruce Caswell, president of Maximus Health Services, a government contractor that handles Medicaid enrollment in 18 states and will run Obamacare call centers for Vermont, Hawaii and Maryland. Maximus starts with estimates of the percentage of a state's uninsured who are expected to buy coverage through its exchange. It then estimates how many will call for enrollment help and calculates the percentage likely to be "deflected" with a robo-answering program ("press 3 if your address has changed"), which is often about 20 percent, said Caswell. It then plugs in the expected length of a call (four and a half minutes for Medicaid enrollees) and out comes an answer: Maximus will need 25 staffers for Hawaii, where about 153,000 adults are uninsured. Many of the groups sending forces into the Obamacare fray are community-based healthcare organizations. Earlier this month, Washington's Healthplanfinder announced grants of $6 million to groups to help people enroll for coverage, including the Whatcom Alliance for Health Advancement. The group will use its grant "to look under rocks if we have to" and find Washingtonians eligible to buy insurance through the exchange, said Deputy Director Elya Moore. "We'll go to community events, health fairs and even the 93-mile 'Ski to Sea' race" from Mount Baker to the coast, Moore said. They don't envision hiring more members of their "access team," who help people enroll in Medicaid and children's health insurance programs. Earlier this month, Colorado named 55 organizations, from community groups like Hilltop Community Resources to Centura, the state's largest hospital system, to help residents sign up for insurance on its exchange. Among them: the Colorado Motor Carriers Association, "the voice of trucking in Colorado." At the federal level, Obama's proposed budget for the IRS next year would allow the agency to hire nearly 2,000 employees, according to a GAO analysis. The IRS will administer subsidies (in the form of tax credits) to help people buy insurance through the state-based exchanges ad level penalties on uninsured adults who don't. Obamacare imposes tricky mandates on employers, such as requiring those with 50 or more full-time workers to offer insurance coverage or pay fines, leading to warnings that companies will have to hire many more employees to help them comply with the law. Most employers, however, are not staffing up. A survey by the Society for Human Resources Management released in June shows 74 percent of employers are sending existing HR staff to training on the healthcare law, and 73 percent are working with their legal staff or outside consultants to understand their options. "Most of our clients are dealing with the requirements of the law with their existing staff," said Randall Abbott, a senior executive in the healthcare reform division at Towers Watson, the consulting firm whose clients are large employers. They may be adding some support staff ... but our experience has been that it's negligible. Additional reporting by Caroline Humer; Editing by Michele Gershberg and Douglas Royalty