The failed US energy giant Enron has been accused of failing to co-operate with Congress as it tries to unearth the reasons for the biggest corporate bankruptcy in American history.

The man making the complaints is Senator Byron Dorgan, who heads one of the nine congressional panels looking into Enron's collapse.

He has accused Enron of not providing important records for about 3,000 controversial partnerships.

Senator Dorgan says the partnerships were used by Enron to keep debt off its highly leveraged balance sheet and to enhance its earnings.

As such, the documents play a significant role in explaining why the company fell apart so swiftly last autumn - and exactly who was involved.

Allegation denied

One of Enron's lawyers, Robert Bennett, called the Senator "terribly misinformed" and insists the Enron has been cooperating fully with the committee.

He says the records are held by the partners concerned, and not by Enron.

This latest spat is likely to be overshadowed by the appearance of Enron's Chief Executive Kenneth Lay at a hearing on Monday.

It will be the executive's first public remarks since the collapse.