Republican National Chairman Bill Brock conceded yesterday that the GOP has filed for years to recognize the problems of working people and called on organized labor to help reshape the party by joining it.

In an unusual appeal for support among normally Democratic union activists, Brock told a labor gathering here that the Republican Party is "up for grabs" and invited unions to join the scramble for influence.

"The line is short," he added sardonically.

Since taking over the party 15 months ago, Brock has talked of broadening its base among blacks, labor and other groups in an attempt to stave off extinction - a task that has been complicated by courtship of unions of "new-rights" conservatives working outside the GOP party structure.

But his remarks in a joint appearance with Democratic National Chairman John White before a Communications Workers of America legislative-political conference went considerably beyond traditional GOP rhetoric.

Brock aides noted that the appearance in itself was significant. They said they couldn't remember the last time a Republican national chairman addressed a union meeting.

In his remarks, which were politely if not enthusiastically received by the crowd, Brock acknowledge what he called a "divorcement" between the party and unions.

He said he was trying to make the "first step" by consulting with top union leaders and urging other party officials to open communication at state and local levels and thereby "force it down through the iceberg" of the party heirarchy.

Asked by a CWA official how the GOP could make itself "palatable" to labor "after years of neglectt, Brock said both parties will have a "knee-jerk reaction" to the Depression of the 1930s, with the Democrats looking to government for answers and the Republicans looking to private enterprise.

Neither stand is exclusively right, said Brock, but the Democrats are credited with reorganizing there are problems to be solved. If the choice is between "someone who recognizes the problem and will give the wrong answer" and "someone who doesn't recognize the problem," he said people will "choose the guy who at least recognizes there is a problem."

Brock's answer is for the Republicans "to recognize a problem and then deal with it in a way that's very tangible," to benefit large numbers of people, including labor, blacks and poor people. He cited Republcian support for college tuition tax credits and job expansion incentives as an example.

Skeptical questions poured in from the audience, prompting Brock at one point to suggest, without success, that some be directed at White.

How can the GOP expect labor support when it sends out fund-raising letters suggesting that AFL-CIO President George Meany is buying elections? one listener asked.

"George Meany is almost a code word in political fund-raising," Brock responded, adding that the party could just as well have used the name of a large corporation president because big business money is increasingly going to Democrats instead of Republicans. "Our people are getting pretty fed up with major corporate approaches too," he said.

Many Republicans oppose the union-backed labor law revision bill, aimed at curbing antiunion tactics used by the big J.P Stevens textile firm and other companies, and Sen. Orrin G. Hatch (R-Utah) calls labor leaders "goons," another listener commented.

Brock declined to comment on Hatch and said he would not try to "explain or apologize for J.P. Stevens."

Brock said afterward he doesn't expect any instant labor conversions to the GOP but he plans to pursue union support "aggressively," among leaders and among rank-and-file workers who, he said, "don't like to be told how to vote by anyone."