Federal investigators posing as senior citizens found that Medicare's operators routinely failed to give callers accurate and complete information about the government's new drug benefit, prompting Democratic critics of the Bush administration program to again request an extension of an approaching enrollment deadline.

The investigators said that about one-third of their calls resulted in faulty responses or no response at all because of disconnected calls. The accuracy rates varied a great deal based on the question, but when it came to one of the most important questions, operators provided the right answer only 41 percent of the time. That question concerned which drug plan cost the least for a beneficiary based on certain drug needs.

"These findings also point to larger problems," said Rep. John Dingell, D-Mich. "Because of inaccurate or incomprehensible information, seniors haven't been given a fair shake. The president should extend the May 15th enrollment deadline and not penalize seniors for the administration's errors."

The investigators with the Government Accountability Office also kept track of how long it took for operators to answer the phone at 1-800-Medicare. For 75 percent of the 500 calls made, the wait was less than five minutes. However, for more than one in 10 calls, it took operators more than 15 minutes to answer the call.

"In one case, we were placed on hold for 54 minutes before being disconnected," the GAO reported.

The investigators also looked at the federal government's Web site, as well as the information described in a handbook sent to all beneficiaries. They found problems there as well.

Program administrators have "not ensured that its communications to beneficiaries and their advisers are provided in a manner that is consistently clear, complete, accurate and usable," the investigators concluded. "Six months have passed since these materials were first made available to beneficiaries, and their limitations could result in confusion among those seeking to make coverage decisions."

Mike Leavitt, secretary of the Department of Health and Human Services, said Wednesday his agency has fixed some of the problems cited by the investigators, particularly the wait times for the Medicare hot line.

"We monitored from the very beginning those calls and we saw the same thing, and worked hard to improve it" Leavitt said. "Over the course of time it has improved. We're now down to 2 or 3 minutes. It was too long, and we responded. ... I can say with some satisfaction that things have improved dramatically."

Leavitt said he continued to oppose any delays in the May 15 enrollment deadline. By then, he said he expects that more than 90 percent of about 43 million Medicare beneficiaries will have prescription drug coverage through Medicare or through other programs, he said.