Republican party leaders were given some election-year advice yesterday: don't let the economy or the Democrats panic you. Take the offensive, or you're going to lose next fall. And President Reagan will run for reelection in 1984.

The advice came from political pros, White House advisers and national party leaders who met with state GOP chairmen the day after Reagan's first State of the Union message.

The chairmen greeted the president's speech as a much-needed pep talk that shored up their resolve during increasingly bad economic times.

"In these times, you need it right from your leader's lips," said Michigan chairman Melvin Larsen. "Everyone needs a sense of direction, and he gave it to us. Once again, he said, 'I'm the leader.' We needed that."

White House political director Edwin Rollins predicted Reagan will seek reelection. "President Reagan is going to be a two-term president," he said.

He urged the chairmen to take the offensive and stick to a national theme based on a "strong image of the president and the Republican party providing leadership."

The chairmen were given plenty of ammunition to counter Reagan critics and were reminded repeatedly that their fates and Reagan's are interlocked.

They also were advised not to be suckered by the Democrats' hardtimes rhetoric. The public, party pollster Richard Wirthlin told them, is willing to give Reagan's economic program time to work.

Wirthlin said two-thirds of 1,500 Americans polled by his firm Jan. 11-18 were willing to give the economic program a year or more before they expect to see its effects. Furthermore, almost 60 percent of those polled think only half or less of Reagan's program has been approved by Congress, he said.

Fifty-nine percent of those surveyed said they thought Reagan's economic program will help the economy, while 32 percent said it would hurt, Wirthlin told the chairmen in a meeting closed to the press. This means Republicans "have a margin of patience" to exploit to their advantage, he said.

More pointed advice came from Eddie Mahe, one of the party's most respected campaign consultants. He said Republicans can't let the Democrats frame the debate over the issues in 1982.

"Force the debate on our terms because if we don't frame the debate they will," he said. "If we debate this election on their terms, we can't win."

Mahe contended that the Democrats in their prepared reply to Reagan's State of the Union address played into Republican hands because the only solution they offered was "to go back to where we were."

"The Democrats are bankrupt," Mahe added. "You didn't hear a single idea in their presentation . . . . Their only hope for 1982 is that we fail."

Mahe suggested that Republicans portray the 1982 elections as a choice between the GOP policies of "hope, opportunity and the future" and the Democrats' "welfare state."

Reagan's New Federalism, he said, gives Republican candidates a way to frame elections as contests between those who want decisions to be made by state and local governments, close to the people, and those who want them made by "bureaucrats in Washington."

The presentations to the state chairmen were designed to bolster their resolve and spirits at a time when high unemployment is causing political problems in many of their states. The White House effort was lead by chief of staff James A. Baker III and Rollins.