Congress probably will have until mid- or late December before it has to clear legislation raising the limit on the amount the government can borrow, the Treasury Department announced Wednesday.

This would be two months later than Treasury had originally anticipated, and the delay buys Democrats time to advance expensive health care legislation before having to take the politically difficult vote to raise the debt limit — assuming Congress waits until the last minute to act, as it has in the past.

Treasury warned that it cannot predict with certainty when the current $12.104 trillion debt limit will be hit.

“The government’s cash flows are volatile, and forecasting a precise date is difficult,” the department said in a release.

In August, Treasury Secretary Timothy F. Geithner wrote to congressional leaders asking them to raise the limit by mid-October. But the next month, Treasury announced it would decrease the amount in the Treasury Supplemental Financing Program — an emergency loan program created in response to the financial crises, from $200 billion to $15 billion — essentially buying more time before the debt limit would be hit.

Corporate tax receipts also have been higher than Treasury anticipated back in August, according to a Democratic aide.

Several Senate Democratic moderates have said they want a vote on increasing the debt limit tied to moving forward on the creation of a special process or commission that would be charged with addressing concerns about the amount of debt the government is projected to run up in the coming years.

House Speaker Nancy Pelosi , D-Calif., opposes creating a commission, preferring that the issue be dealt with by congressional committees, and Senate leaders have not embraced the idea. But some compromise with moderate Senate Democrats might be necessary if a debt-limit bill is moved on its own.