Betsy DeVos speaks at a Trump rally in Michigan on Dec. 9. (Andrew Harnik/Associated Press)

Democrats are pushing to delay next week’s confirmation hearing for Betsy DeVos, President-elect Donald Trump’s pick for education secretary, until a federal watchdog agency finishes reviewing her background and financial investments for possible conflicts of interest or other ethics concerns.

The Senate Committee on Health, Education, Labor and Pensions (HELP) is scheduled to hold a confirmation hearing Jan. 11 for DeVos, a Michigan billionaire. She is one of several Trump nominees whose vast wealth and considerable financial holdings have overwhelmed the bipartisan Office of Government Ethics, which is responsible for vetting Cabinet nominees.

In a letter to Senate Democrats on Saturday, the head of the ethics office said that Trump and Republican leaders are breaking with decades of precedent by pressing for Cabinet confirmation hearings to take place before ethics reviews are completed.

Walter M. Shaub Jr., the director of the ethics office, wrote that it would be “cause for alarm” if the Senate were to go forward with hearings on nominees who have not been fully vetted because of the potential for “unknown or unresolved ethics issues.

Republican HELP committee leaders have no plans to postpone DeVos’s hearing in light of the concerns about the unfinished ethics review, according to a GOP committee aide.

Holding hearings without completed ethics paperwork is not unprecedented, the aide said, pointing to documents showing that Rod Paige, who served as education secretary under George W. Bush, submitted his ethics paperwork eight days after his confirmation hearing in 2001.

But Republicans pressed Democrats to ensure that President Obama’s appointees were fully vetted before their confirmation hearings. In February 2009, in the first few weeks of Obama’s administration, Sen. Mitch McConnell (R-Ky.) — whose party was then in the minority — outlined that expectation in a letter to Senate Majority Leader Harry M. Reid (D-Nev.).

DeVos is a major Republican donor who has focused the bulk of her energy and political contributions on pushing to expand charter schools and taxpayer-funded vouchers for private and religious schools. She has not worked in public education nor served in public office, and is one of eight Trump nominees that Democrats have flagged for extra scrutiny.

In her responses to a HELP committee questionnaire last week, DeVos did not directly address questions devoted to identifying potential conflicts of interest. She wrote that she would consult with the Office of Government Ethics to identify and resolve any problems.

Sen. Patty Murray (Wash.), the HELP committee’s ranking Democrat, said that she wants to delay next week’s confirmation hearing until after the ethics office has a chance to finish its job.

Eli Zupnick, Murray’s spokesman, said that every Obama appointee that came before the HELP committee over the past eight years had completed their ethics review before the confirmation hearing.

“It would certainly be concerning if nominees break from standard practice and don’t submit their ethics paperwork in advance of a hearing,” Zupnick said. “Making sure that nominees don’t have conflicts of interest and will truly put families across the country first is one of the most important jobs that the Senate has in this process, and we remain hopeful that it will not be rushed through.”

Six other HELP committee Democrats last week asked DeVos to furnish details about her contributions to and involvement with advocacy and lobbying groups, writing in a letter that they needed more information about her role in this “complicated web of political and not-for-profit organizations” to evaluate her potential conflicts of interest.