Democratic leaders of the House Appropriations Committee yesterday informally approved a $4.5 billion plan for jobs and recession relief that would reshuffle and modestly expand President Reagan's proposal.

But it ran into opposition behind the scenes from some liberal urban Democrats who complained that it would not go far enough in helping the neediest, and House Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.) indicated that changes may be made.

The Democratic plan, which is scheduled for action Friday by the full Appropriations Committee, differs from Reagan's in providing less for such projects as highways, transit and ports and more for weatherization of low-income housing, jobs for young people and the elderly, retraining for displaced workers, economic development and feeding programs for women and children.

In all, it would spend about $400 million more than Reagan proposed, according to Democratic aides.

But some Democrats complained that the proposal went too far in trying to forestall a presidential veto and objected to what they called its rural tilt. An aide to one noted that maternal and child health programs got $10 million, while $200 million was provided for rural water and sewer grants.

There was no immediate word from the White House as to whether the Democratic proposal would satisfy Reagan, although the committee Democrats had clearly tailored it to win presidential support.

As the Democrats were hammering out their proposal, a House Republican task force suggested some general guidelines for jobs legislation, and 17 northeast and midwest Republicans disclosed a letter they sent to Reagan earlier this month warning that his 1984 budget endangers the GOP's base of support in the industrial North.

"Federal programs for targeted economic development, energy conservation, new energy technologies, urban mass transit, education and assistance to the poor are not expendable," said the letter, whose signers included Rep. Silvio O. Conte (R-Mass.), ranking Republican on the Appropriations Committee. "Yet they are the very programs singled out by your budget office for additional cuts or, in some cases, elimination."

The proposed jobs guidelines included emphasis on labor-intensive programs and high-unemployment areas and provision of jobs most likely to help women and young people. The leadership-appointed group also urged "adherence to the basic spending limitations recommended by the administration."

For the pending "phase-one" jobs bill, Rep. James M. Jeffords (R-Vt.), spokesman for the group at a news conference, said he favored less money for big public works and more for economic development and dislocated workers. He said the Democratic proposal "sounds like it's a package I would be more likely to support" than Reagan's.

In related action, the House Committee on Education and Labor approved legislation to create a jobs program similar to the Depression-era Civilian Conservation Corps (CCC). It would cost $60 million this year and $300 million annually in succeeding years, employing about 100,000 people a year in such activities as flood control, wildlife protection and restoration of urban parks.

On another front, a House Ways and Means subcommittee quickly endorsed legislation to clear away tax obstacles that the administration and farm organizations feared might undercut participation in the federal program for reduction of surplus crops.

Department of Agriculture and Treasury officials urged approval of a bill before March 11, the deadline for the payment-in-kind (PIK) plan to give farmers surpluses in return for not planting this year.

A Senate panel is expected to begin work on a similar bill next week.

The House Agriculture Committee, meanwhile, voted to recommend to the Budget Committee a fiscal 1984 agriculture and nutrition budget that could be $4 billion more than Reagan is seeking. The farm committee suggested major increases in food stamp outlays ($1.4 billion more), in an emergency loan fund for farmers ($1.2 billion) and in rural business loans ($1 billion).