House Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.) told the nation's mayors yesterday that President Reagan will have to bow to growing pressure for an emergency jobs bill, and two conservative Senate Republicans split with the administration by announcing a jobs program of their own.

A top White House official, however, said Reagan remains staunchly opposed to public works or public service jobs as temporary and unproductive.

"We certainly can afford to have a $5 billion to $7 billion jobs program this year," O'Neill told a meeting of the U.S. Conference of Mayors. "I truly believe that by March the White House will be sending in a [jobs] program." O'Neill added later that he was "confident the president will break down" on the jobs proposal.

In a separate move, Sens. Orrin G. Hatch (R-Utah), chairman of the Labor and Human Resources Committee, and Dan Quayle (R-Ind.), who heads its employment subcommittee, proposed to spend $2 billion to create about 250,000 public service jobs this year.

They said the money would be channeled through existing programs to create "needed" and "worthwhile" jobs in fields ranging from day-care centers to nursing care at veterans' hospitals.

A broad array of economic proposals filled the air as politicians of every stripe rushed to offer solutions to the nation's high unemployment:

* A committee of the mayors' conference voted overwhelmingly to push a $31.5 billion urban aid plan that would include public works jobs, anti-recession aid, a new federal loan program and emergency food and shelter. The mayors voted to finance the program by urging Congress to defer indefinitely the final 10 percent of Reagan's income tax cut, due in July.

* A group of conservative Republicans in Congress, rejecting Reagan's proposal to freeze spending only for domestic programs, said the freeze should be extended to the president's planned defense buildup.

* Sen. Robert J. Dole (R-Kan.), chairman of the Finance Committee, said the quickest way to stimulate jobs might be to increase general revenue sharing for the cities.

* A more ambitious proposal came from Rep. Augustus F. Hawkins (D-Calif.), who would spend $10 billion this year to create 1 million public works and public service jobs--or 20 percent of all those out of work at least 15 weeks, he said.

Asked about the prospect for public works jobs, Richard S. Williamson, Reagan's assistant for intergovernmental affairs, said: "The president's position has not changed in his opposition to that type of program. Jobs bills of this sort . . . have usually proven unproductive and have not created jobs. The answer to unemployment lies in long-term, private sector jobs."

Williamson said Reagan would prefer such steps as increasing aid to displaced workers and offering tax credits for hiring the long-term unemployed.

The Quayle-Hatch bill does propose a voucher system under which jobless workers would get 75 percent of their supplemental unemployment benefits to give to a prospective employer. It also includes $100 million to expand a year-old retraining program for dislocated workers and new rules to force more federal procurement in depressed areas.

Reagan can fight the public service jobs at his political peril, Quayle warned, adding that public pressure probably would force the president to accept the plan. "He's going to get a jobs bill. The question is what it is going to look like," Quayle said.

At the mayors' conference, San Francisco Mayor Dianne Feinstein (D) also brushed aside the White House objections. "I don't think public works jobs need be dead end," she said. "If people want to work and you can provide a job, that is not a dead end. These Depression levels of unemployment are unacceptable to most people."

Feinstein's mayoral committee voted to recommend dropping the third year of the tax cut, which would save about $76 billion, although some mayors argued that the savings should be used solely to reduce the huge federal deficit. But Mayor Arthur Clark of Waltham, Mass., arguing that unemployment is fueling the deficit, convinced the mayors to tie the endorsement to their $31 billion urban aid plan.

That plan would increase funding for community development grants, to $5 billion, and for revenue sharing, which at $7.5 billion would restore such aid for states as well as cities. It also would earmark $10 billion for urban public works, $2 billion in countercyclical fiscal aid and $5 billion for a new Reconstruction Finance Corp. to provide loans and subsidies to ailing cities and businesses.

Rep. James R. Jones (D-Okla.), chairman of the House Budget Committee, agreed that the July tax cut should be dropped, and he urged that the Pentagon's budget authority be cut by $33 billion a year.

The call for reduced defense spending included seven conservative House and Senate Republicans, who said that Reagan's spending freeze should cover the Pentagon as well as apply more evenly to domestic benefit programs. The group would make major exceptions only for payments on the national debt and for newly qualified recipients in benefit programs.

A spokesman, Rep. Newt Gingrich (R-Ga.), called the Reagan freeze "a halfway house that picks up on the right words but still has the wrong details."

Dole surprised the mayors by suggesting that increasing revenue-sharing funds "could be one of the quickest ways to put money into the cities, and maybe even the states, without trying to create some new jobs structure. I'm sure if the money was available, you'd be able to use it to create jobs."

Senate Majority Leader Howard H. Baker Jr. (R-Tenn.) said that any jobs program should be modest, take effect quickly and not include "make-work" jobs.