A sweeping new study of the nation's bankruptcy system has found major problems in the administration of bankruptcy cases, from judges who ignore parts of the law to companies and individuals who abuse the system.

Although the bankruptcy system is working reasonably well on a day-to-day basis, it faces a serious loss of credibility if the flaws are not corrected, according to bankruptcy judges and lawyers associated with the study released yesterday.

The most serious problem identified in the study, according to the experts, is the failure of many judges to follow the congressional mandate to protect the interest of creditors. Congress in part changed the bankruptcy law in 1984 because of a perception that debtors were treated too leniently, but the study indicated that either the new rules are not being followed or have not had their intended effect.

"In some areas of the country, the judges are not doing what they are supposed to be doing," said George C. Paine, federal bankruptcy judge in Nashville and one of the overseers of the survey of more than 1,000 judges, trustees and other lawyers involved with bankruptcy cases.

Experts cited the sheer crush of bankruptcy filings in recent years as one of the prime reasons judges are not always complying with federal bankruptcy rules. Unusually stringent provisions of the bankruptcy code, including requirements that hearings start within a certain length of time, were also cited as reasons for noncompliance.

The survey also indicated that lawyers are not willing to challenge judges who ignore the law. This problem is exacerbated, experts said, because bankruptcy lawyers are a relatively small part of the legal community and often appear time and time again before the same judges.

Whatever the reasons for noncompliance, bankruptcy lawyers said Congress needs to rethink some of its recent efforts to add new requirements to the system, or provide more resources and judges.

Sen. Dennis DeConcini (D-Ariz.), one of the Senate's leading authorities on bankruptcy, said he was "surprised at the extent of {noncompliance}" shown in the survey. But "it is a little too early to tell what changes we need," he said, adding that he expects hearings to be called on the matter.

The survey released yesterday was carried out during the past year by the American Bankruptcy Institute, a group of professionals involved in bankruptcy matters. It comes amid a staggering increase in the volume and complexity of bankruptcy cases around the nation that experts say has resulted from the economic distress in some parts of the country as well as the growing use of the bankruptcy code as a business reorganization device.

According to figures released with the study yesterday, a record 477,843 individuals and businesses filed for bankruptcy in the year ended June 30, 1986, and throughout the first nine months of the current fiscal year, 411,309 bankruptcies have been reported.

The study was primarily intended to assess the effectiveness of the 1984 amendments to the bankruptcy code, but it also highlighted several broader trends. Among the key findings:

There is a significant degree of noncompliance by judges with various legal requirements of the code, although this varies greatly by judicial circuit. For instance, Congress in 1984 required bankruptcy courts to schedule hearings within 30 days when creditors seek to lift the bankruptcy code's automatic prohibition against their efforts to collect their debts or seize collateral. However, about one-half the survey respondents said the deadlines were not met on at least some occasions, while one-quarter said they were hardly ever met.

There is "considerable perceived abuse of the bankruptcy process." Virtually all the bankruptcy professionals surveyed perceived some abuse, while 21 percent perceived a "great deal of abuse." Respondents differed widely on the nature of the abuses, but among the problems cited were individuals hiding assets from creditors or understating their worth.

A large group of respondents, the survey showed, believe that many companies are abusing the system by filing under Chapter 11 with no intention of reorganizing, but only to delay business failures. Under Chapter 11 of the federal bankruptcy code, debtors are temporarily protected from creditors while devising a plan of reorganization.

The 1984 changes enacted by Congress that were studied by the institute did not dramatically change the bankruptcy system. Only 37 percent of the respondents thought the system was better as a result of the changes, while 42 percent perceived no changes.

The changes were designed to prevent individual debtors from abusing the system.