WASHINGTON – Tens of millions of families are paying people to handle their tax returns this season, but government auditors and the IRS warn that many of them are unlicensed and may be unqualified.

About half of the tax preparers registered with the Internal Revenue Service are not required to have licenses or pass tests to prove their competence.

The returns they handle can be riddled with errors, and taxpayers who’ve spent hundreds of dollars for the help can be left facing audits and fines.

“Tax returns are the most important document a family fills out every year, and you’d think there would be some minimum standards or training for people they pay to prepare their taxes,” said Chi Chi Wu, an attorney for the National Consumer Law Center. “But anyone can set up a card table on a sidewalk and prepare taxes for a living.”

A proposal to tighten standards for preparers, however, appears stalled by Republicans’ concerns over giving more power to the IRS.

The top Republican and Democrat on the Senate Finance Committee last year proposed empowering the IRS to require paid tax preparers to pass a competency test and be licensed. The measure was yanked from consideration last year, when Republicans balked in the wake of a scandal over IRS targeting of conservative political groups.

Democrats on the committee say the Republican majority appears to have no appetite for the proposal by the committee’s chairman, Sen. Orrin Hatch, R-Utah, and ranking member, Sen. Ron Wyden, D-Oregon.

“This is not a complex political issue, it’s about protecting honest taxpayers from fraud,” said Lindsey Held, a spokeswoman for Wyden.

Julia Lawless, spokeswoman for committee Republicans, said Hatch hopes to bring it back up soon.

But some Republicans on the committee, including Indiana Sen. Dan Coats and Iowa Sen. Chuck Grassley, said they’re still leery of giving more power to the IRS.

In a statement, Coats said the proposal gives the IRS “unfettered authority” despite the agency’s inappropriate scrutiny of conservative groups’ applications for non-profit status.

Republicans say the scandal reflected the Obama administration’s excessive use of power on a range of issues, including immigration and gun control.

“There may be a path forward on this, but it will be very difficult to enact during an administration that is famous for regulatory overreach,” Coats said.

According to the IRS, more than half of 150 million tax returns filed last year were done by paid preparers.

Some, including certified public accountants and attorneys, must be licensed in their own professions. Others take part in a voluntary IRS program, in which they undergo training to be included in an agency database that consumers can check.

But, according to IRS data, roughly half of paid preparers have neither professional licenses nor have completed its training.

Two years ago, Congress’ investigative arm, the Government Accountability Office, sent investigators posing as waitresses and mechanics to 19 tax-preparers. Only two calculated refunds correctly.

Others made errors ranging from giving a taxpayer a refund $52 less than what they should have received, to claiming a refund that was $3,718 more than the taxpayer was entitled to get.

Costs for preparing returns ranged from $160 to $587, according to the report. Explanations for why some returns cost more included claims that the work was more expensive in the mornings than in the afternoons.

Another study by the government’s watchdog, examining IRS data from 2006 through 2009, found errors in half of the returns prepared by taxpayers and 60 percent of those done by paid preparers.

Wu said the National Consumer Law Center’s own investigation also found errors, as well as outright fraud.

The group sent someone posing as a single mother whose child lives mostly with the father and who does not qualify for an earned income tax credit. Yet preparers told her to claim the credit anyway, reasoning that the father made more money.

Concerned about the impact of mistakes and bad advice on taxpayers, the IRS moved in 2010 to require paid preparers to take tests and train annually in order to be licensed.

The requirements were tossed out three years later in the face of challenges by some tax-preparers who said the IRS had no authority to impose rules on its own.

Hatch and Wyden’s proposal would have given the IRS the authority.

Democrats are calling for the bill to be reconsidered. Large tax preparation companies, such as H&R Block, support it, too.

H&R Block spokesman Gene King said the company also backs a licensing requirement. Its preparers must pass a test then go through annual training, he said.

But free-market groups, including Americans for Prosperity, oppose the idea, saying the cost and time of testing and licensing will prove onerous to small businesses, hurting their ability to compete with big tax-preparation chains.

They argue that tax preparers are already subject to laws and stiff penalties for fraud or not practicing due diligence in preparing returns accurately.

In a statement, Grassley also raised concern about giving the IRS more power.

“The challenge for Congress now is to strike the right balance between protecting taxpayers from any rogue tax-preparers and protecting taxpayers from an IRS with a history of abusing power,” he said.

Nina Olson, the IRS’ national taxpayer advocate, said at a Senate Finance Committee hearing in 2014 that the government cannot keep tabs on thousands of tax-preparers.

Without licensing, she said, “taxpayers have no easy way to determine if the preparer they’re hiring can do the job.”

Kery Murakami is the Washington, D.C. reporter for CNHI’s newspapers and websites. Reach him at kmurakami@cnhi.com