WASHINGTON — Reigniting a partisan fight over banking regulations, President Barack Obama intends to nominate former Ohio Attorney General Richard Cordray to lead the Consumer Financial Protection Bureau, which was a central feature of a law overhauling the rules that govern the financial sector.

Obama plans to announce the nomination formally Monday, the White House said Sunday. Republicans immediately threatened to block Cordray’s Senate confirmation.

In choosing Cordray, Obama bypassed Elizabeth Warren, a favorite of consumer groups, who has been assembling the agency as a special adviser to the White House and to Treasury Secretary Timothy Geithner.

The agency will officially begin its oversight and regulatory work on July 21. Its role is to be a government watchdog over mortgages, credit cards and other forms of lending.

“Richard Cordray has spent his career advocating for middle-class families, from his tenure as Ohio’s attorney general, to his most recent role as heading up the enforcement division at the CFPB and looking out for ordinary people in our financial system,” Obama said.

But Sen. Richard Shelby of Alabama, the top Republican on the Senate Committee on Banking, Housing and Urban Affairs, said Republicans would block Cordray as well unless Obama seeks changes in the agency.

“Although this deadline has been known for nearly one year, President Obama waited until the last possible moment to act. For months he has ignored Republican concerns about the lack of accountability at the CFPB and its potential adverse effect on the economy,” Shelby said. “Until President Obama addresses our concerns by supporting a few reasonable structural changes, we will not confirm anyone to lead it. No accountability, no confirmation.”

News Washington correspondent Mary Orndorff contributed to this report.