D.C. Mayor Marion Barry yesterday proposed a sweeping reform of the city's narcotics laws, including a tough new ban on the sale of drug paraphernalia and increased penalties for selling drugs to minors.

As part of his 1981 legislative program, Barry proposed a package of bills to combat the city's rising crime rate, in some cases by simply updating laws already on the books. Included in the package are bills to combat "child snatching" in custody cases and another bill to more strictly regulate the sale of secondhand merchandise.

Barry, who unveiled his legislative package at his regularly scheduled monthly press conference, was short on specifics about many of the individual parts of his program. But he emphasized that the overall thrust was to streamline city government, reduce spending and improve administrative procedures throughout the government.

The emphasis on managerial efficiency, as opposed to proposals for sweeping new programs, in many ways reflects the liberal city government's new focus on fiscal restraint made necessary by having to grapple with a worsening budget crisis.

In the public safety area, Barry proposed strenghtening the fire safety code to require the installation of automatic sprinkler systems in many new and existing commercial, public and residential buildings.

Barry also proposed severe restrictions on the circumstances under which a D.C. Superior Court could assume jurisdiction in child custody cases. The measure is aimed at cutting down on the number of so-called child snatching incidents, where a parent who is denied custody of a child in one jurisdiction can effectively kidnap the child, bring the child into Washington and get another custody hearing in the District court system.

In many cases, especially with his crime proposals, the mayor's bill mirrored legislation already being considered by the council.

The mayor's narcotics proposals would categorize all drugs according to their potency with use or possession of the most potent drugs carrying the heaviest penalties. That is the pattern currently used in federal narcotics laws, under which most local drug violations are prosecuted. it is similar to one narcotics law being proposed by council member David A. Clarke (D-Ward 1) as part of his criminal code revision. Barry's drug paraphernalia measure would be similar to those already enacted in several suburban jurisdictions, which ban the sale of such items as paper to roll marijuana cigarettes and water pipes. He did not specify what new penalities should be imposed for drug offenses.

The revenue provisions of the mayor's program include one bill that would create "a stable and relaible source of funding" for the District's share of Metro construction costs. He proposed creation of a special Metro account in the D.C. treasury, with money earmarked from certain transportation-related taxes, such as the motor vehicle registration fees, the sales tax on parking garage fees and the gasoline gallonage tax.

The mayor also called for revision of the District's income tax return forms so that they would conform with the federal returns, to make them easier to file. He also proposed business tax credits for firms in the city that hire D.C. residents. The tax credits would amount to $1,200 per employe against the taxes that the business must pay the city Barry said the increased employment would offset the loss of the taxes to the city's treasury.