WASHINGTON - The Department of Defense on Friday acknowledged that its health care system has serious problems, and top military officials proposed changes to make the services' almost 600 hospitals and clinics safer.

'The people I met with admitted that mistakes have been made,' said U.S. Rep. David L. Hobson, R-Springfield, after meetings with the military's top health officials. 'Frankly, I find this refreshing, and it reassures me that we will be able to get some changes made to make patients safer and to prevent future problems.'

One of the changes the military promised is an external review body to examine decisions made by military health care officials.

'This isn't the only fix that needs to be done. It's not over with,' said Scott Milburn, Hobson's press secretary.

The proposed changes follow a seven-part series published in the Dayton Daily News Oct. 5-11.

The Daily News reported that the military's health care system lacks the most significant safeguards protecting civilians from medical malpractice. Military doctors are not required to have malpractice insurance, they can practice in states where they do not hold licenses and they are virtually immune from being sued for medical malpractice, the series reported.

'They took this up to the top (of the Department of Defense), and the response was 'face this and fix it,'' Milburn said.

Hobson, who sits on the House subcommittee that approves funding for the Pentagon, met separately this week with Rudy DeLeon, Undersecretary of Defense for Personnel and Readiness, and Dr. Ed Martin, acting Assistant Secretary of Defense for Health.

In both meetings, Hobson said he stressed that Congress is taking seriously allegations of mismanagement and inadequate care "and expect positive changes to be made quickly to ensure that military health care improves."

Martin appeared Friday before representatives of veterans groups and military family organizations in an invitation-only meeting and vowed to correct problems brought to light in the Daily News series.

''These are real problems and these are real people,'' Martin said, according to a representative of one of the groups who took notes. Martin told the group Secretary of Defense William Cohen ''understands the situation and wants them to make it right,'' the representative said.

The meeting, in Alexandria, Va., was hosted by two groups, the Military Coalition and the National Military/Veterans Alliance, and was called at the Pentagon's request so that Martin could address the the newspaper articles, sources said.

''He said they know there are problems in the private system as well, but that that doesn't relieve them of responsibility,'' the representative said.

Milburn said the military is considering changes in the way it reports to the National Practitioner Data Bank, a computer database of civilian and military doctors with records of incompetence and malpractice. The Daily News series reported that the military accounted for two of every 1,000 malpractice reports to the database, even though it employs about 18 of every 1,000 doctors in America.

'(Military) officials told Hobson that these changes are being made because the military's policy for reporting physicians to the NPD has been inadequate in the past,' says a prepared statement from Hobson's office.

The statement also says the military has forbidden doctors practicing under 'special' Oklahoma licenses from treating patients, and an aide to Undersecretary DeLeon confirmed that those physicians have been put under direct supervision.

The newspaper series reported that Oklahoma granted the license to military doctors even though they didn't meet the qualifications to be civilian doctors. Hobson, Milburn said, also is concerned about the difficulty state medical boards have monitoring military doctors. Although military doctors must have a state license, they do not have to be licensed in states where they practice - a requirement for nearly all other doctors in America.

'How do states monitor doctors practicing outside their boundaries?' Milburn said. 'That's a very big problem. It's a bigger problem to take on.'

Correcting some of the most significant problems addressed in the series could require legislative changes to fix, Milburn said.

For example, he said, it's up to Congress to change a legal doctrine that prevents lawsuits for medical malpractice involving active-duty military members.

DeLeon said Friday the Pentagon has been aware of the need to improve the military's health care system.

''You raised some issues,'' he said of the series. ''I really don't want to get into a point-counter-point on the specifics of the stories, but we're working on those concerns.''

Of the health care system, he said simply, ''There are problems.''

Portions of the Daily News series were published in more than a dozen other newspapers, and ABC's 20/20 aired a report Oct. 10 based on the newspaper's findings. The Army, Navy and Air Force weekly newspapers, which are distributed to military bases worldwide, also published significant parts of the series, and The Stars and Stripes newspapers ran parts of the series.

Although the military has not disputed any of the facts in the series, it has been trying to counter the effects of the publicity by issuing news releases and publishing articles of its own in response.

In a letter to the editor published in the Army Times this week, three top officials in each branch of the service lauded the military's health care system.

"We believe that our military health services system is one of the highest quality systems in the world," said the letter, which was signed by Vice Adm. Harold M. Koenig, surgeon general of the Navy; Maj. Gen. Michael K. Wyrick, deputy surgeon general of the Air Force; and Lt. Gen. Ronald R. Blanck, surgeon general of the Army.

However, in another article, published in at least one Navy newspaper, Koenig invited readers with 'questions about anything contained in the (Daily News) articles' to contact him directly or the Navy Bureau of Medicine and Surgery.

'If you ever have a question about the appropriateness of care at a Navy Medical facility, we want to know about it, right away,' he wrote.

Hobson, in his prepared statement, said: 'I am much more confident than I was earlier that there is a willingness on the part of the military to solve these problems. If they're serious about solving these problems, they've got a partner right here. I hope we can continue to work together to fix it.'