A Senate Democratic policy committee has endorsed an economic platform for the 1984 campaign that calls for major new federal commitments in job training, aid to education and help for declining industries to strengthen the competitiveness of the American economy.

A 43-page report by the Senate task force, appointed by Minority Leader Robert C. Byrd (D-W.Va) and headed by Sen. Edward M. Kennedy (D-Mass.), has been sent to Senate Democrats prior to consideration by the Democratic Caucus this week, aides said.

A caucus vote on the document is expected before Congress adjourns this year. House Democrats are also preparing proposals for new economic policies.

The report's central contention is that the American economy is being disrupted by rapid technological change and is threatened by growing import competition, requiring a strong response by the federal government.

But the report pointedly disowns any attempt at "central planning," arguing that federal aid to companies, workers and state governments can be used as leverage to reduce structural unemployment and improve the economy's performance. The goal of a Democratic economic policy should be "neither central planning nor aimless drift," it says, accusing the Reagan administration of permitting drift to occur.

There are no cost estimates in the report, but the plan reportedly would require up to $10 billion a year in federal spending once it was fully in effect.

The senators propose establishment of a White House-level economic advisory council of 20 leaders from government, labor, management and the public appointed by the president. The council would have the status of an independent federal agency.

It would investigate problems in declining industries like steel, or those severely threatened by import competition, like semiconductors or consumer electronics.

Industries seeking trade relief would, in most cases, be required to prepare a plan for "adjustment and modernization" that could include wage or work-rule concessions by employes, commitments by management to modernize aging plants, retraining for displaced workers, job-security guarantees for those who remain employed, and regulatory changes.

The president would take such plans into consideration in deciding whether to grant import relief, the report states.

A series of compromises that were concluded at the end of last week produced an endorsement of the report by the task force members, aides said.

One compromise involved proposals to establish a federal development bank to channel financial support to key industries, patterned after the Reconstruction Finance Corporation of the New Deal. Kennedy supported this. Other senators strongly opposed it, and the report recommends that the new economic council merely study the issue further.

The report also shuns the label of "industrial policy," the term that Democratic policy planners and academics have been using to describe the changes they seek. The term apparently has become too hot to use, following a barrage of attacks this fall from prominent economists and Reagan administration officials who argue that the United States is not "deindustrializing" and who warn that government attempts to help industry would lead to protectionism and interference.

With the report, the Democratic senators hope to move back on the offensive by proposing the themes and some of the particulars of a Democratic economic policy. "This is a positive statement of things that can be done to make industry more competitive," said an aide to Sen. Carl M. Levin (D-Mich.), a task force member.

The report proposes to modify the unemployment insurance program by giving the states several options for helping workers whose jobs have been eliminated by plant closings or are threatened by employment cutbacks. Such workers in threatened industries could take time off from work for retraining and receive up to 20 hours of unemployment benefits per week, the report suggests. Or, in companies where cutbacks are inevitable, workers could resign before being laid off and receive unemployment insurance benefits while enrolled in training.

There are also recommendations for increased federal aid for vocational education and for "disadvantaged" and "gifted and talented" pupils.

To encourage job creation, the report proposes to furnish federal financial support to state economic development agencies that make loans and grants to new businesses. And the document recommends several steps to encourage business investment in research and development, including the establishment of technology centers at state universities, patterned after the Agricultural Extension Service, where federally supported research could be transferred to companies.