WASHINGTON – The White House is weighing a package of business tax breaks – potentially worth hundreds of billions of dollars – to spur hiring, according to people with knowledge of the deliberations.

Among the options under consideration are a temporary payroll tax holiday and a permanent extension of the now-expired research and development tax credit, which rewards companies that research new technologies within the United States.

With the unemployment rate expected to rise again in new jobs numbers due out today, panic is setting in among many Democratic candidates who fear it is too late for President Obama to convince midterm voters that he understands the depth of the nation’s economic woes and can fix them.

White House officials cautioned that no tax cuts have been settled on and that a more limited measure could emerge.

Policy staffers are debating a range of options. For example, a payroll tax holiday – a top priority of many business groups – could be applied only to new hires or extend to current employees. It could be limited to small businesses or extended to larger firms.

If administration officials can agree on a policy path, it is not clear that it would be approved in the current environment on Capitol Hill. And even if Congress did approve new measures to bolster the economy, they would probably come too late to make a difference in the lives of voters before the midterms.

“Substantively, there is nothing they could do between now and Election Day that would have any measurable effect on the economy. Nothing,” said the Brookings Institution’s William Galston, a domestic-policy adviser to President Bill Clinton.

Obama has an incentive to act: Tax cuts enacted during the Bush administration are scheduled to expire in January, and Democrats – accused by Republicans of plotting to let them vanish – feel compelled to do something before the midterms.

Obama campaigned on a pledge to let cuts expire for the richest 2 percent of households, but some Democrats say the economy is too weak to raise anyone’s taxes right now. And they fear a backlash from small-business owners who would be hit with higher taxes.

Pairing targeted business tax breaks with an extension of middle-class tax cuts could help alleviate those problems.

Permanently extending the research credit would cost roughly $100 billion over the next decade, tax analysts said. And depending on its form and duration, a payroll tax holiday could cost more than $300 billion. While significantly less than last year’s stimulus package, both ideas would be far more dramatic than anything the White House has so far acknowledged considering.

More spending on infrastructure, particularly transportation projects, is also under discussion. But it would be easier for a package comprising only tax cuts to “avoid the stain of a ‘bailout’ or ‘stimulus’ label,” said one official familiar with the talks.

The president could roll out additional measures as soon as next week. Senate leaders hope to begin debating the tax issue in late September.