The California Democrat made the stark comments in a Capitol Hill hallway interview as she left a caucus lunch where the standoff with Republicans over a government funding bill -- known as a continuing resolution or CR -- was discussed. She was asked whether she thought her party would vote to pass or block a GOP bill to keep the government open ahead of a Friday deadline.
"Shutting down the government is a very serious thing. People die, accidents happen. You don't know. Necessary functions can cease," she said. "There is no specific list you can look at and make a judgment: 'Well everything is going to be just fine.' You can't make that judgment. So, I think it's a last resort. And I'm really hopeful we don't get to it."
Feinstein said she had not made her mind up about whether to vote for the measure.
Her comments differ from a press statement issued by her office earlier in the day in which she said she would vote against the funding bill unless it included the Dream Act, a bill to help young immigrants affected by the expiring Deferred Action for Childhood Arrivals program.
GOP leaders are refusing to attach the immigration measure to the continuing resolution, and it's at the crux of the dispute between the parties.
"I don't know if we did today," Feinstein said, looking towards an aide when asked about the press release.
In that statement, Feinstein is quoted as saying, "I said in December that I wouldn't vote for a CR without the Dream Act, and I won't do so now."
Pressed on why she might vote to shut down the government if it could cause people to die, Feinstein acknowledged it's a "big risk."
Feinstein's press office didn't immediately return messages seeking comment on the discrepancy about her position on the bill or why she thinks people will die if the government shuts down.
Despite her press release, Feinstein insisted she had not decided how she would vote.
"I don't know how I would vote right now on a CR, OK?" she said before ending the interview with a polite "thank you."
Feinstein is 84 and running for a sixth term this cycle. She is the top Democrat on the Judiciary Committee.