Employers in all sectors plan to increase hiring in the third quarter of 2012, as reflected in improving employment numbers. However, economic uncertainties regarding the looming “fiscal cliff” may constrain efforts to expand staff levels.

United States non-farm employment rose by 163,000 jobs in July, according to the U.S. Department of Labor, including 25,000 manufacturing jobs, marking 10 straight months of job growth in the sector. However, with impending Congressional decisions concerning expiring tax breaks and enforced spending cuts, manufacturers may have to reign in their hiring plans.

Most of the increase in manufacturing jobs was in the durable goods category. Seasonal layoffs were down in the motor vehicle and parts industry this summer, which contributed to an employment increase of 13,000. The fabricated metal products industry also showed continued growth with 5,000 new hires.

Wanted Analytics found that demand for technical jobs in manufacturing has risen 13 percent from 2011, with engineering, management, production and sales-related jobs topping the list. However, more managers and supervisors were hired than technicians or production workers.

Overall, these numbers reflect a generally positive trend for hiring in 2012.

Employers project that they will hire 10.2 percent more college graduates in 2011-2012 over the 2010-2011 period, according to respondents to the National Association of Colleges and Employers’ (NACE) Job Outlook 2012 Spring Update. Original projections were for 9.5 percent growth before mid-year adjustments.

The Simply Hired July 2012 Outlook showed similar optimism, noting that job openings were increasing nationwide by 3.3 percent over April figures, with a higher number of openings in 49 of the 50 major metropolitan areas. Additionally, seasonal summer hiring was proceeding at a higher rate.

CareerBuilder’s 2012 U.S. Mid-Year Job Forecast anticipates more growth this year than in 2011, based on employer surveys. The percentage of employers expecting to hire full-time, permanent employees climbed to 44 percent in mid-year 2012, up from 35 percent during the same period in 2011. Those expecting to hire part-time employees rose to 21 percent from 15 percent last year.

However, a separate government survey of households found that hiring dropped by 195,000 jobs in July, the largest decline since June 2011. “[T]he household survey may be more accurate at turning points in the economy because it is more likely to pick up hiring and firing at small companies and new firms that may be under the government’s radar,” Bloomberg News reports.

“When you look at both the surveys smoothed out over three months, the divergence almost disappears and it feels like a mediocre labor market,” Bruce Kasman, chief economist for JPMorgan Chase & Co., told Bloomberg. “There’s a sort of sigh of relief that we’re not slipping into something particularly weak, but we’re also not holding strong momentum here by any means.”

Overall, Kasman continued, “the downward shift in the momentum may be starting to arrest itself.”

Meanwhile, fears about an impending “fiscal cliff” may curb hiring prospects.

The “fiscal cliff” refers to an economic doomsday scenario that would occur if Congress does not act to renew certain policies set to expire by the end of the year. Chief among these changes are the Bush tax cuts, the payroll tax cut and the automatic spending cuts included in the debt ceiling deal Congress enacted last summer.  The concern, according to the Congressional Budget Office, is that these tax increases and spending cuts will so negatively affect U.S. gross domestic product (GDP) that the country will fall back into recession.

According to the Washington Post‘s Wonkblog, “the mere anticipation of this change will reduce GDP growth by 0.5 percent” in 2012.

The reduction in GDP is occurring as industry employers cut spending across the board. “Executives at companies making everything from electrical components and power systems to automotive parts say the fiscal stalemate is prompting them to pull back now, rather than wait for a possible resolution to the deadlock on Capitol Hill,” the New York Times explains.

In addition to reducing spending on new technology investments and factory upgrades, manufacturers are also tightening hiring budgets. “The fiscal cliff is the primary driver of uncertainty, and a person in my position is going to make a decision to postpone hiring and investments,” Timothy H. Powers, CEO of Hubbell Inc., an electrical product manufacturer, told the Times.

Congress could avoid the fiscal cliff triggers by enacting a “grand bargain” or renewing some of the tax cuts before the December deadline.