U.S. Attorney Earl J. Silbert told a Senate subcommittee yesterday that proposals to revise the District of Columbia's outdated criminal code will result in "confusion and chaos" in the city courts and will adversely affect law enforement here.

Silbert, whose office prosecute all serious local and federal crimes, also said that sentence lengths included in the proposals are "far too low" to provide the public with "necessary protection from criminal conduct."

Silbert is a member of the D.C. Law to the Congress for its approval a massive overhaul of the city's criminal code - which was last revised in 1901.

His remarks yesterday were included in a minority report to the commission's final proposal. The report was written by Silbert and signed by three other commission members, including D.C. Corporation Counsel John R. Risher Jr.

The Law Revision Commission, a panel of 19 lawyers and community representatives, laboured for two years to produce its proposal for a new basic criminal code. Congress has control over approval of the code until early 1979, when jurisidiction over the city's criminal laws passes to the mayor and City Council, under provisions of limited home rule granted in 1973.

Sen. Thomas F. Eagleton (D-Mo.), chairman of the Senate subcommittee that handles D.C. legislative matters, conducted more than four hours of hearings yesterday, which included testimony from commission members who disagree with Silbert's comments.

A companion House Subcommittee is holding similar hearing.

Commission chairman Stephen I. Danzansky told Eagleton yesterday that the proposed basic criminal code - which Silbert has called "piecemeal" - is a foundation upon which the remainder of the code can be revised in the future. The commission's proposal deals only with crimes against persons and property, such as murder, robbery, sex offenses and theft. Other crimes included in the current D.C. Code, such as gambling, prostitution and drug violations, presumably will be considered by the City Council when it gains control over the criminal laws.

Silbert contends that if only a portion of the code is revised, judges and jurors will be faced with an "unworkable and impractical" situation of applying new and old laws at trials. Chief judge Harold H. Greene of the D.C. Superior Court has said, however, that while that point has "some validity" it should not" stop the work of the commission in its tracks."

Danzansky said the sentence terms proposed by the commission coincide with the actual prison time spent by offenders who are sentenced in D.C. Superior court, where judges apply variety of minimum and maximum terms, depending on the crime. About 70 percent of all offenders are released by the D.C. Parole Board after they have served the minimum term.

The commission proposal attempts to limit a judge's sentencing discretion through a system of classes of crimes, with sentence ranges for each class and guidelines for judges to follow in imposing sentences. The proposal eliminates the parole board's authority to release prisoners.

Danzansky, pointing up some of the conflicting reaction to the commission's proposal, noted that while Silbert thinks the sentences are too short, the American Bar Association though the recommended terms were too long. Officials of the D.C. Department of Corrections, meanwhile, fear the new sentencing structure will double the city's prison population, Danzansky said.

Both Silbert and Judge Greene expressed concern that the new sentence structure would only be applicable to those crimes revised by the commission. Thus, if a defendant were convicted of two crimes - one of which was revised by the commission - he would be sentenced under both the new and old procedures, a situation Silbert and Greene said could result in unfairness.

In testimony before the House subcommittee Greene suggested that the new sentencing procedures be made applicable to all sentences. Silbert said yesterday that the commission should hold off until the entire code is revised. Chairman Danzansky suggested a formula whereby a defendant could be sentenced under both the new and the old system. Eagleton said the problem said "not quite as simple" as the commission "made it out to be."