By Curtis Tate in Washington, D.C. --

The Obama administration had been hoping for months to have the support of Alaska Republican Sen. Lisa Murkowski for the head of its new consumer watchdog, but Murkowski said Tuesday that she has "great concerns" about the agency's structure and that it shouldn't have a director without changes Republicans want.

In a test vote Thursday, Senate Republicans are poised to block the nomination Thursday of former Ohio attorney general Richard Cordray to head the Consumer Financial Protection Bureau. Tuesday, Republicans were nearly united in opposition.

Murkowski said Cordray is "competent and capable," but would have too much power.

"There's no accountability within this proposed agency," she said. "And I haven't seen anything that's given me any assurance."

Murkowski said she didn't sign a letter with 44 Republicans in May opposing any nomination to the bureau because she wanted "flexibility." But Tuesday, she sided with her colleagues.

"I don't think we want anybody in there in that position until we can address some of the concerns that were raised in that letter," Murkowski said.

Over the weekend, the White House launched a lobbying campaign in the home states of several Republican senators, including Alaska, aiming to build support for Cordray.

While Murkowski said the White House had contacted her staff, she hasn't had direct conversations with anyone in the Obama administration about Cordray's nomination.

Senate Minority Leader Mitch McConnell, R-Ky., said Tuesday in a floor speech that he didn't know if President Barack Obama to had reached out to any Republican senators.

"If he's picked up the phone to talk these issues over with anybody in our conference, I haven't heard about it," McConnell said.

The agency began its work in July, but the absence of a director limits its authority. The White House Sunday released a report that said without a director, the bureau can't regulate non-bank financial institutions, which include payday lenders, debt collectors, credit reporting agencies and non-bank mortgage lenders and servicers.

In October, the Senate Banking Committee approved Cordray's nomination without the support of any of the panel's 10 Republicans. Also that month, 37 state attorneys general, including Democrats and Republicans, endorsed Cordray's confirmation.

Sen. Scott Brown of Massachusetts is the only Republican who said he'd back Cordray. He was one of three Republicans who voted for the Dodd-Frank financial reform bill last year that established the consumer protection bureau. The agency's primary architect, Elizabeth Warren, is Brown's Democratic opponent in the Massachusetts Senate race.

Republicans want changes to the bureau's structure: a board of directors, rather than a single director; a budget that's subject to congressional appropriations instead of independent funding; and more checks and balances over the agency's authority.

Ken Edwards, the federal policy counsel with the Center for Responsible Lending, a consumer advocacy group, said those changes are unnecessary and would hurt the consumers the bureau is trying to protect.

"Structural changes would weaken the bureau," he said. "It would keep it from being the watchdog it was designed to be."