By David Lawder

WASHINGTON (Reuters) - Congressional Republican leaders said on Wednesday they were committed to delaying a tax penalty provision in the health care law and would use oversight powers to hold President Barack Obama's administration "accountable" for problems with its launch.

Republican leaders have complained about a lack of transparency surrounding problems with the launch of the government run health care insurance exchanges on October 1, saying that House Democrats were briefed by administration officials, but Republicans were not.

House Majority Leader Eric Cantor said on Wednesday that Republicans would seek to delay a requirement of the 2010 Affordable Care Act, known as "Obamacare," that all Americans obtain health insurance or face a tax penalty starting next year - at least until questions over the rollout of the Healthcare.gov website and detrimental effects of the law can be cleared up.

"The rollout of Obamacare is nothing short of a debacle, and the American people are now fearful of their healthcare," Cantor told reporters after a meeting with House Republicans. "With so many unanswered questions and the problems arising around this rollout, it doesn't make any sense to impose this one percent mandate tax on the American people."

Republicans have opposed the healthcare law, Obama's signature domestic policy achievement, on grounds that it is an unwarranted expansion of the federal government.

House Speaker John Boehner said that Republicans would use their oversight powers to conduct hearings into problems with the main federal insurance exchange website, as well as other problems with the law, including reports that it is causing employers to drop their own health care plans.

"Whether it's Obamacare or issues with the Department of Defense, It's our job to hold them accountable. And when it comes to Obamacare, there's a lot to be held accountable," Boehner said.

He said the party would continue to press for government spending cuts, despite House Republicans' failure to halt funding for Obamacare in a fight this month over a government shutdown and the federal debt limit.

(Editing by Vicki Allen and Grant McCool)