The SEC chief's split with the administration shows how hard it may be for a broad overhaul of financial rules to overcome turf wars among various regulators and for a consensus to be reached on Capitol Hill.

SEC Chairman Mary Schapiro said Wednesday she opposed the plan discussed Tuesday night by Treasury Secretary Timothy Geithner and other administration officials that would chip away at the SEC's own powers. She said giving any new entity authority over mutual funds would lessen the government's protection of investors -- her agency's core mission.

"I would question pretty profoundly any model that would try to move investor protection functions out of the Securities and Exchange Commission," Schapiro told reporters at the agency's headquarters. "Investor protection is woven through everything that happens in this organization."

Many of the SEC's responsibilities -- such as companies' financial disclosures, shareholder rights, stock trading, brokerage firm practices and mutual funds -- involve investor protection, Schapiro said.

"So it's not a discrete thing that gets moved away without really damaging the fabric of the entire investor protection regime," she said.

But the SEC's effectiveness as protector has been called into question after revelations in December that the agency failed to detect the massive pyramid scheme run by money manager Bernard Madoff, despite red flags raised to its staff by outsiders over the course of a decade. Schapiro, an Obama appointee who became SEC chairman in January, has taken several actions intended to strengthen and speed the agency's enforcement efforts and tighten its internal processes.

The plan the administration is weighing would centralize the enforcement of laws that protect consumers of financial products, such as credit cards, mortgages and mutual funds. That mission is now spread across a patchwork of federal and state agencies, including the SEC, Federal Reserve and Federal Trade Commission.

Any changes to the nation's financial oversight would require congressional action. And it's unclear whether lawmakers will unite behind a single approach this year.

Rep. Barney Frank, D-Mass., who heads the House Financial Services Committee, favors in principle changes that would bolster consumer protection, but in this case "there's no proposal right now to endorse," said his spokesman, Steve Adamske.

Adamske declined to comment on the issue raised by Schapiro concerning mutual funds.

Schapiro's comments marked her first sharp public breach with the administration over an overhaul of rules designed to prevent another financial crisis. Schapiro in recent weeks has told Congress, which is debating the changes, that she thinks the SEC must play a key role as an independent watchdog protecting investors in any new regulatory system.