Nielsen Holdings PLC has asked the Media Rating Council, the media industry’s measurement watchdog, to pause accreditation for its national TV rating service, a move that would leave the measurement giant’s core product without the organization’s seal of approval for the first time since the 1960s.

The company chalked up the request to concerns regarding its panel, the group of people the company uses to assess ratings in the U.S., as well as efforts to modernize its national TV measurement product.

“We believe hiatus is the best course of action at this time and will allow us to focus on innovating our core products, continuing to deliver data that the industry can rely on and ultimately creating a better media future for the entire industry,” Nielsen said in a statement.

The MRC audits and accredits media measurement processes to instill confidence in often complex or murky systems used to measure results.

A suspension of its accreditation could further erode the confidence of Nielsen’s TV network customers and advertisers after concerns were raised about challenges maintaining its panel system during the pandemic and other issues that led to an undercounting of viewers. But short-term effects likely won’t hit the company’s bottom line, said Douglas M. Arthur, an analyst at Huber Research Partners LLC, in an email.

Nielsen’s customer contracts don’t require the company to have accreditation, and there is still not much competition for prime-time TV ratings data, he said.

“I have been hearing about competitive threats for 20 years,” Mr. Arthur said. “Nothing so far.”

However, losing such a stamp of approval could give customers more leverage when a new contract comes up, he said.

The Video Advertising Bureau, which represents many large TV networks, in July called for the MRC to suspend Nielsen’s accreditation partly because of the panel’s problems during the pandemic.

The MRC had planned a meeting Thursday to vote on the question.

In the meeting, which still took place, the organization’s television committee voted on Nielsen’s request. The MRC said in a statement that the committee has referred the matter and its recommendations to the full MRC board for its consideration. A hiatus period could last for up to six months, and a service has an option to request a second six-month hiatus, the MRC said.

Nielsen’s request to pause accreditation hasn’t satisfied the VAB, the trade organization said.

“After months of Nielsen’s very public insistence that there is nothing wrong with their ratings data, but now facing a slam-dunk VAB case for accreditation suspension, Nielsen has essentially announced ‘you can’t fire me, I quit’ just hours before the MRC suspension vote process is activated,” the VAB President and Chief Executive Officer Sean Cunningham said in a statement.

Companies have long criticized Nielsen’s ratings system, which is the underpinning of nearly all transactions in the $70 billion traditional TV advertising business in the U.S. But the criticisms boiled anew after the MRC this spring said that Nielsen had under counted TV viewers by up to 6% during the month of February 2021.

According to Nielsen data cited in the MRC report, the audiences that weren’t initially counted should have cost marketers an added $39 million to $234 million for ads in February, depending on whether it was a 1% or 6% miss.

At the time, Nielsen confirmed that there were problems with its panel, according to news reports.

The undercount prompted new calls for change from the upper echelons of media.

“We’re competing with the likes of Google and Facebook, where they have the best data, the cleanest data, and you compare that with this antiquated system,” Discovery Inc. CEO David Zaslav said during a second-quarter earnings call on Aug. 3. “I don’t have a lot of hope for Nielsen,” he added. “I think somehow, as an industry we’re just going to have to work our way out of it, from a technology perspective, and leave them in the dust because they can’t get it together.”

Nielsen has launched products to measure streaming views, and said it would have a national product that measures TV across platforms, including traditional and internet-connected TV, by fall 2024.

Write to Alexandra Bruell at alexandra.bruell@wsj.com