MELBOURNE, FLA., JUNE 22 -- President Reagan today kicked off a nationwide drive against Democratic fiscal policies that he said have produced "a bloated government" and pledged that "any tax-hike bill that makes it into the Oval Office won't make it out alive."

In three speeches here that carefully avoided any reference to administration foreign policies, Reagan hammered on what he said was the need for "a radical reform of the budgetary politics that pays for today's excesses with tomorrow's money."

Aides said the president will detail this "reform," which he calls an "Economic Bill of Rights," in a speech at the Jefferson Memorial on July 3.

They said this "bill of rights" will include some new proposals and an exposition of economic philosophy as well as Reagan's familiar appeals for line-item veto authority and a constitutional amendment requiring a balanced federal budget. Reagan asked again today for enactment of these "powerful measures."

His speeches in this high-technology center on Florida's "space coast" were devoted largely to a denunciation of federal government spending. Many of the passages were throwbacks to his attacks on "tax and tax, spend and spend" policies in his earliest campaign speeches more than 40 years ago.

Reagan's return to time-tried themes was no accident. White House spokesman Marlin Fitzwater said polls taken for the White House show that voters are most supportive of Reagan when he is drawing a "stark choice" between his administration and the Democratic Congress on budget policies.

Reagan acknowledged this, too. In a picnic lunch speech to the chamber of commerce, he said that polls taken after his nationally televised speech last week showed voters more receptive to his budget views than to the administration's Persian Gulf policy or his claims of success at the recent economic summit in Venice.

Fitzwater said that Reagan's speeches today, which also included brief remarks at the Melbourne airport and an outdoor address to employes of the Dictaphone Corp., came in the first of a half-dozen stops he will make across the country to address budget issues before he begins an extended vacation at his California ranch in mid-August.

The president's flat rejection of any tax increase comes despite his own budget proposal, which contained $22 billion in new revenues, including about $4 billion in new taxes. His stance today would seem to rule out accepting a compromise agreed to by Democratic leaders last week on a $1 trillion spending plan for fiscal 1988 that would cut military spending increases below inflation levels unless Reagan agrees to about $19 billion in new taxes.

However, Fitzwater told reporters on Air Force One en route to Florida that White House chief of staff Howard H. Baker Jr. is continuing to work with congressional leaders in an effort to achieve a compromise.

Reagan's difficulties in transforming his rhetoric on budget issues into a policy acceptable to Congress were illustrated today by the reaction of local congressman Bill Nelson (D-Fla.), who accompanied the president to Melbourne aboard Air Force One and was rewarded with praise for past support on fiscal issues.

Rep. Nelson, talking to reporters after Reagan had flown back to Washington, said the president had been "gracious" in his remarks but took issue with his attack on congressional Democrats.

Nelson also suggested that Reagan had misrepresented his position on the trade bill in his speech at the Dictaphone Corp.

Calling for a Senate trade bill that "opens markets," Reagan denounced the House-passed trade bill as "antijobs, antigrowth and anticonsumer." He also left the impression that Nelson agreed with him, praising the lawmaker for being "on our side" and for "doing what is right."

Nelson emphasized afterward that he supported the trade bill, including the controversial Gephardt Amendment, which has been denounced as "protectionist" even by some Democratic leaders.