WASHINGTON, Jan 23 (Reuters) - A fired partner at accounting firm Andersen challenged Congress on Wednesday by refusing to testify without immunity at a hearing into the firm's audits of the collapsed Enron Corp., while lawmakers unveiled bills aimed at preventing similar business disasters.

On the eve of the first of nine congressional hearings over six weeks into the Enron debacle, a lawyer for former Andersen partner David Duncan told Congress that Duncan would exercise his constitutional Fifth Amendment right not to testify on Thursday unless he was granted immunity.

Duncan was dismissed in mid-January by Andersen, which alleged he ordered the destruction of documents once he learned the Securities and Exchange Commission was seeking information on Enron's financial reporting.

Committee chairman Rep. Billy Tauzin said no immunity from prosecution using Duncan's congressional testimony would be granted to him without Justice Department consent.

"I will not provide immunity to anyone without consent of the Justice Department who is doing a criminal investigation," the Louisiana Republican said on CNN.

"I have not received such a green light to this date, as to whether or not they change their mind I can't say," he said.

Enron fell in just weeks last year from No. 7 on the Fortune 500 list of large companies to filing the largest bankruptcy in U.S. history on Dec. 2, wiping out billions of dollars in equity and devastating employee retirement funds.

Lawmakers on Wednesday added two bills to the growing body of post-Enron legislative proposals aimed at reforming retirement fund laws and oversight of accounting firms.

Connecticut Sen. Chris Dodd and New Jersey Sen. Jon Corzine, both Democrats, said they would introduce a bill to restrict independent auditors from providing non-audit services to audit clients, double the size of the Securities and Exchange Commission's audit staff, and take other steps.

Massachusetts Democratic Rep. Edward Markey introduced a bill to remove limits on the ability of defrauded investors to recover financial losses caused by accounting firm fraud.

As lawmakers searched for a policy response to Enron, congressional investigators probed for explanations of how the Houston-based company -- once the world's largest energy trader -- fell apart so quickly in a cloud of debt and questionable accounting that raised questions about Andersen's role.

Giuffra, the lawyer for Duncan, said his client had only on Tuesday gotten access to his files at Andersen.

Giuffra, a partner at the high-powered law firm of Sullivan & Cromwell, said Duncan sought full disclosure of the truth. He said his client remained committed to cooperating with all pending investigations concerning Enron.

Ken Johnson, a spokesman for Tauzin, told Reuters that Duncan would have to appear in person on Thursday to invoke his right not to testify rather than send a sworn statement.

"The committee is going to insist on his (Duncan's) appearance ... If he thumbs his nose at us, then we'll consider our options, including contempt of Congress," Johnson said.

Legal experts have said that immunity offered in exchange for congressional testimony could play havoc with the Justice Department's criminal probe of Enron and Andersen.

"We do expect him (Duncan) to take the Fifth. I'm still holding out a faint hope that he might overnight decide he ought to make a clean breast of it," Rep. James Greenwood, the Pennsylvania Republican who chairs the oversight and investigations subcommittee of the House Energy and Commerce panel , said on CNBC.

Tauzin's House Energy Committee also issued subpoenas for two Andersen managers -- Michael Odom and Nancy Temple. The committee said they would appear at Thursday's hearing.

The committee had planned to subpoena Andersen Chief Executive Joseph Berardino, but decided not to after Andersen offered an alternate witness, Dorsey Baskin. Andersen said Baskin is an expert on auditing standards, including work papers and client files.

Along with Justice and the SEC, the Labor Department and at least eight congressional committees are investigating.

Senate Finance Committee Chairman Max Baucus, and the panel's ranking Republican, Charles Grassley of Iowa, sought permission from Enron to release the company's tax returns to the public.

The lawmakers asked Enron for written permission to "release to the public information contained in Enron's federal consolidated tax returns or any tax information related to Enron's affiliated companies or partnerships that is not included in the consolidated tax returns."

Last week, a tax watchdog group said Enron had not paid U.S. income taxes in four of the five years through 2000, while receiving tax refunds close to $400 million in the period.

In further Enron developments, Vice President Dick Cheney's office maintained its refusal to turn over details of how the White House formulated its energy policy -- including Enron's involvement -- despite increased pressure from Congress.

The investigative arm of Congress, the General Accounting Office, has been seeking more information about contacts between industry and the administration's energy task force, headed by Cheney.

"Our statement of Aug. 2 (rejecting the request for documents) stands," senior Cheney aide Mary Matalin told Reuters.

The GAO is contemplating going to court to force the White House to provide information. Environmentalists say they were largely shut out of the policy-making process.

Four Democratic senators involved in probes of Enron sent a letter to the GAO on Wednesday supporting its efforts to pressure Cheney for further details. Nampa-Reuters