Dick Cheney, the US vice-president, on Sunday refused to release records of meetings with company executives to discuss energy policy, increasing the chances of a historic legal challenge from Congress as it probes the money and power trail left by the once-mighty Enron.

The General Accounting Office, Congress's leading investigative arm, is threatening to take the Bush administration to court for withholding details about how it developed its energy policy. The energy policy taskforce, headed by Mr Cheney, had six meetings with various companies, including Enron, last year. Democrats in Congress have suggested that campaign donations by Enron and others gave them unprecedented sway over policy.

David Walker, head of the accounting office, has said he will decide whether to sue the White House for Mr Cheney's files after tomorrow's State of the Union address by President George W. Bush.

It would be the first legal challenge of its kind and would be likely to set a precedent for conduct of future administrations in using outside advisers to help formulate national policy.

A defiant Mr Cheney said in a television interview it would be inappropriate to release his records or provide a list of those business leaders who had helped formulate energy policy, as the accounting office has requested.

He said he had already provided Congress with financial documents and other background material, and suggested providing anything more would violate his and the president's constitutional right to consult with outside groups about policy and protect the privacy of those with whom they meet.

"It is important to preserve our ability to get unvarnished advice from anybody we want on any subject we want without having to put it out in the newspapers or give it to members of Congress," he said.

Mr Cheney also dismissed the most recent demands as politically motivated, tied to "the question of Enron and some efforts by some of my Democratic friends on the Hill to try to create a political issue out of what's really a corporate issue".

While drafting the energy policy last year, Mr Cheney met Kenneth Lay, who resigned last week as Enron chairman. Enron executives separately met Mr Cheney's staff several times. Enron was the top contributor to Mr Bush and a substantial donor to the Republican party in the last presidential elections.

The administration has redoubled its efforts to distance itself from the Enron debacle but a New York Times/CBS News Poll at the weekend showed a majority of Americans believe the Bush administration is hiding something or lying about its dealings with Enron.

Following Enron's collapse in December, the company's ties to the White House have come under growing scrutiny. Late last week, the Bush administration ordered federal agencies to review more than $60m in federal contracts with Enron and Andersen, the accounting firm that audited Enron's books.

For the past nine months two Democratic congressmen, John Dingell and Henry Waxman, have been demanding release of details about the Cheney-led taskforce, which drafted a White House energy policy calling for more oil and gas drilling and a revived nuclear power programme.