WASHINGTON — Vice President Kamala Harris said on Thursday that the 2.5 million women who have left the work force since the beginning of the pandemic constituted a “national emergency” that could be addressed by the Biden administration’s coronavirus relief plan.

That number, according to Labor Department data, compares with 1.8 million men who have left the work force. For many women, the demands of child care, coupled with layoffs and furloughs in an economy hit hard by the pandemic, has forced them out of the labor market.

“Our economy cannot fully recover unless women can participate fully,” Ms. Harris said on a video call with several women’s advocacy groups and lawmakers, essentially reiterating the argument she made in a Washington Post op-ed published last week.

On the call, the vice president painted a dire picture of the situation that millions of American women are facing during the pandemic. “In one year,” she said, “the pandemic has put decades of the progress we have collectively made for women workers at risk.”

“Women are not opting out of the work force,” Representative Rosa DeLauro, Democrat of Connecticut and the chairwoman of the House Appropriations Committee, said after attending the panel. “They are being pushed by inadequate policies.”

As part of its $1.9 trillion relief plan, the Biden administration has outlined several elements that officials say will ease the burden on unemployed and working women, including $3,000 in tax credits issued to families for each child, a $40 billion investment in child care assistance and an extension of unemployment benefits.

Ms. Harris said on Thursday that the package would “lift up nearly half of the children who are living in poverty in our country,” a claim backed by a Columbia University analysis of the plan.

A recent Quinnipiac poll showed broad support for the Biden administration’s proposal, but so far, Republicans have not embraced it. Democrats aim to pass the plan using a fast-track budgetary process known as reconciliation, which would allow them to push it through the Senate with a simple majority. Senator Mitt Romney, Republican of Utah, unveiled his own child tax credit proposal this month, but it was promptly panned by colleagues in his party.

“I think that there is absolute reason to believe that Republicans should support this,” said Senator Patty Murray, Democrat of Washington, who participated in the call. But she added that her party had ensured that the proposal could go forward without the Republicans.

Child care remains an issue for working mothers, and it was a major theme of the round table on Thursday. Nearly 400,000 child care jobs have been lost since the outset of the pandemic, Ms. Harris said. The closings of small businesses and the loss of millions of jobs have created the “perfect storm” for women, particularly for Black business owners, she added. “The longer we wait to act,” she said, “the harder it will be to bring these millions of women back into the work force.”

The administration’s relief proposal would provide some $130 billion to assist in the reopening of K-12 schools, a major component of child care. But how and when to do so — and how to explain the decision-making to Americans — has proved to be a stumbling point for the president and his advisers.

President Biden has promised to reopen as many schools as possible in the first 100 days of his administration, a pledge that has been questioned by teachers’ unions that want to be assured of safety measures before schools reopen. On Thursday, Ms. Harris kept her remarks on schools limited, saying the plan would “provide funding to help schools safely reopen.” Ms. Harris said in an appearance on the “Today” show on Wednesday that “teachers should be a priority” to receive vaccinations.

Several representatives from women’s advocacy groups participated in the call with Ms. Harris, including Fatima Goss Graves, the president of the National Women’s Law Center. She said that the vice president did not go into “granular” detail about school reopenings but that the group stressed other topics, including the importance of direct payments to struggling families.

“People are barely keeping it together right now,” Ms. Goss Graves said. “I was gratified to hear that she understood and spoke with urgency around getting this investment done.”

As the pandemic drags on, the statistics for women are indeed bleak.

A report published last year by researchers at the University of Arkansas and the Center for Economic and Social Research at the University of Southern California found that female employment began plummeting almost immediately once the coronavirus took hold last spring. Since then, the researchers found, women have shouldered a heavier load than men when it came to providing child care.

Non-college educated women and women of color have been disproportionately affected. Another report, published in the fall by the Brookings Institution, showed that nearly half of all working women have low-paying jobs. Those jobs are more likely to be held by Black or Latina women, and they are in sectors, such as dining and travel, that are among the least likely to return soon to a degree of normalcy.

Ms. DeLauro said she emphasized to the vice president and other attendees that the relief proposal should not contain a “Band-Aid” fix to help women through the pandemic. She instead proposed that Ms. Harris and others think of the relief package as the first step in a longer process to reduce child poverty, reform the child care industry and expand family leave policies.

“There is no normal to go back to,” Ms. DeLauro said. “What we ought to be doing is thinking about how we deal with transformational change.”