America's corporate regulators need more resources to prevent future company collapses like that of energy giant Enron, the chief of Congress's investigative unit says.

David Walker, head of the General Accounting Office, said the Securities and Exchange Commission is "increasingly strained" in fulfilling its regulatory mission.

"There is a growing mismatch between the SEC's responsibilities and its resources," Mr Walker told the Senate Banking Committee.

He said that not only the SEC, but also laws governing companies, accountants and banks, needed to be updated.

Problems for the SEC were stated to be

• low pay compared to other federal law enforcement agencies
• high employee turnover
• ever-expanding amount of work

In 2001, the SEC reviewed only about 16% of the annual corporate filings it received, or about half of its annual goal of 30-35%, he said.

Mr Walker, himself an accountant, is leading efforts to force Vice President Dick Cheney to allow access to records of his energy task force.

Enron... provides a loud alarm that the current system may be broken and in need of an overhaul

David Walker

"As the largest corporation failure in US history, Enron... provides a loud alarm that the current system may be broken and in need of an overhaul," he said.

"The current reporting and accounting model is inadequate," he added. "The timeliness and usefulness of current reporting is also an issue."

Houston-based Enron filed the largest-ever US bankruptcy on 2 December. Thousands of jobs and billions of dollars in equity were lost.

An in-depth internal inquiry ordered by Enron's board alleged that senior Enron managers used a web of off-the-books partnerships to manipulate financial results and fool investors while enriching themselves by tens of millions of dollars.

Ten congressional committees, including Senate Banking, are investigating the matter, as is the SEC and Justice Department.

Mr Walker, who is Comptroller General, has impeccable Republican credentials, and was a volunteer working for the presidential campaign of George Bush Sr.

Despite this partisan background, Mr Walker said his team was ready "to do our job", arguing that the GAO had the right to get the information, because the energy task force was funded by taxpayers.