Fairfax County should consider raising its retirement age from 50 to 55 to keep its pension system on sound footing, according to a consulting firm’s report unveiled Tuesday.

The long-awaited report by AON Hewitt and PRM Consulting Group otherwise found that the retirement health benefits and pensions received by county workers were about average compared with other public employees in the region.

Overall, the consultants’ “Post-Retirement Benefits Review” said the county’s pension plans offer employees a reasonable incentive to spend most of their careers in public service and retire early on a plan designed to protect them against an erosion in their standard of living, no matter how long they live.

For example, a typical county worker who retires at 61 after 21 years of service on a $65,000 salary would be eligible to receive a lifetime benefit of as much as $27,051 a year. The total cost of that benefit — expressed as the amount required now to purchase a financial instrument that would pay such a benefit every year — would be $419,671, of which the county contributes about 74 percent. And it doesn’t include the extra $55,818 that early retirees receive as a supplemental benefit until they can collect Social Security.

The report — which was released Tuesday during a meeting of the Board of Supervisors’ Personnel and Reorganization Committee — said a police officer who retires at 51 after 26 years with a $90,000 salary would receive a lifetime benefit worth more than $1 million, of which the county contributes about 64 percent. Firefighters or other uniformed public safety personnel who stepped down at 51 after 26 years of duty with a $90,000 salary would collect a lifetime benefit valued at $994,851, of which the county contributed 73 percent.

Thomas O.S. Rand, principal with PRM, said Fairfax County’s retirement health benefits and pensions were “right smack on the average” compared with public employees in the federal government, the commonwealth of Virginia, the city of Alexandria, and the counties of Arlington, Loudoun, Montgomery, Prince George’s, and Prince William.

The report said that, in addition to raising the retirement age, the county should also reconsider the formula for retirement eligibility that combines age with years of service, the report said. Instead of the rule of 80 — the sum of age and years of service — the board should perhaps raise this to 85, it said.

But the report fell short for some members of the Board of Supervisors, who said the consultants failed to examine the fiscal health of the county’s pension funds or analyze the merits and feasibility of switching to the type of retirement plan that most private-sector employees receive. “I was disappointed,” said Supervisor Patrick S. Herrity (R-Springfield).

The report comes as governments across the region and the country continue to grapple with public pension liabilities following the worst recession in decades. A key part of Maryland Gov. Martin O’Malley’s (D) budget plan this year includes shifting the cost of teacher pensions to counties, while Virginia Gov. Robert F. McDonnell (R) has called on state workers to foot more of the bill for their retirement benefits.

Fairfax County offers a traditional pension, known as a defined-benefit plan, that guarantees retirees a certain level of benefits for life. Those types of pensions have all but disappeared in the private sector, which now mostly offers employees defined-contribution plans, such as the 401(k). In those plans, employers contribute a fixed amount to employees’ retirement plans but do not guarantee the level of benefits a retiree will ultimately receive.

“I expected a robust discussion of the advantages and disadvantages of a defined-contribution plan, versus the one we have with our employees, said Herrity, who whipped out a copy of the original proposal that called for a study of the county’s retirement benefits. The motion, adopted March 2010, specifically called for a report on the relative advantages of the two types of plans and the feasibility of switching.

Supervisor John C. Cook (R-Braddock) said he was surprised that the consultants failed to analyze the retirement benefits in light of reduced funding ratios between the county’s pension liabilities and the value of its pension funds. The ratio of one fund fell below 70 percent because of the recent recession, requiring the county to commit more taxpayer dollars to the pension funds.

Robert L. Mears, executive director of the Fairfax County Retirement Administration Agency, said the county’s three pension portfolios have already recovered lost ground on shrewd investments since the recession ended. County officials said the bigger threat to long-term fiscal health is tweaking the eligibility criteria to make sure that there will be benefits for retirees who are living longer than they used to.

“I thought what we got was very valuable,” said board chairman Sharon S. Bulova (D). But she also would have liked more context. “It would have been nice if we had a look at what other major employers in the area were doing, like Inova or WMATA,” she said, referring to the Northern Virginia hospital system and the Washington Metropolitan Area Transit Authority, the agency that runs Metro.

Rand also said that although the report contained no recommendations on specific action, it suggested that the board might also review the contradictory aims of the Social Security supplement and its Deferred Retirement Option Program, known as DROP.

Rand said the Social Security supplement essentially rewards early retirement, yet DROP — which allows workers who are eligible to retire to accumulate a lump sum while continuing to work for three years — urges them to stick around.

Still, he said the consulting firm found that the DROP program is “arguably” no cost to the county, which is unusual for offering such a program to all of its general workers. Most such programs apply only to public safety employees, Rand said.