WASHINGTON — President Obama on Monday seized on the fifth anniversary of the 2008 financial collapse to warn that House Republicans would reverse the gains made and willfully cause “economic chaos” with the uncompromising stands they have staked out on looming budget deadlines.

“Budget battles and debates, those are as old as the republic,” Mr. Obama said before a friendly audience assembled in a White House annex. But, he added, “I cannot remember a time when one faction of one party promises economic chaos if it can’t get 100 percent of what it wants.”

A bloc of conservative House Republicans have said that unless Mr. Obama’s signature health insurance law is delayed or repealed, they will not support financing for government operations in the new fiscal year starting Oct. 1 or an essential increase in the nation’s borrowing limit in mid-October.

Failure to act on federal funding would provoke a government shutdown; even worse, failing to increase the debt limit would leave the government unable to pay bills and creditors and ultimately threaten the nation’s default.