Luiz Robert Simmons, 33-year-old member of the Maryland House of Delegates, formally opened his campaign for the Republican nomination for Montgomery County executive yesterday by accusing the Democratic incumbent, Charles W. Gilchrist, of not being a vocal enough critic of Reaganomics.

Seeking to put distance between himself and Republican President Reagan on the issue of federal layoffs, which have hit traditionally recession-resistant Montgomery, Simmons charged Gilchrist with showing a similar (to Reagan) "lack of respect and sensitivity to the institution of public service and public employes.

"The administration of Charles Gilchrist has undermined the confidence and morale of county workers," Simmons told a crowd of about 100 friends and supporters in a noon press conference at the county's Republican Party headquarters. "He has, through his aides and his appointments, replaced the pursuit of excellence in government with the politics of cronyism."

Montgomery is home for 19 federal agencies, employing 41,300. A total of 46,000 county residents--about 12.4 percent of the population--is employed by the federal government, according to the county's public information office. With historically secure government jobs now threatened by layoffs, public service employes could prove a potentially pivotal county voting bloc that would look beyond party affiliation when voting for county executive.

Gilchrist's executive assistant and labor specialist, Edmond F. Rovner, replied that Simmons "is unencumbered by information . . . . Charlie reduced the county work force by 200 last year without a single person going out on the street." He added that it was Reagan, not Gilchrist, who laid off federal workers in the county.

Simmons' only announced opponent for the Republican nomination, 34-year-old banker Joseph C. McGrath, is appealing an elections board ruling that he is ineligible to run because he has not lived in the county long enough. A former Democratic candidate for executive, John P. (Jack) Hewitt, has switched his party affiliation to Republican and has a campaign committee on file with the elections board, but he has not decided whether to run.

Gilchrist, who is expected to announce his candidacy next month, faces primary challenges from Rockville businessman Wade Dunn and retired county employe Athlyn B. Waller.

Despite the county's 2-to-1 majority of registered Democrats, Simmons said he believes he can beat Gilchrist because of his credentials as a moderate-to-liberal Republican, and because of what he called voter dissatisfaction with the incumbent.

Part of that dissatisfaction, Simmons said, comes from Gilchrist's inaction in combating the county's increasing crime rate, including incidents of racial violence.

Simmons said Montgomery leads the state in incidents of cross burnings and swastika paintings and "the county's efforts to date have largely been in the area of speech-making against hatred, hand-wringing and hand-holding.

"It will be the position of my administration that if you paint a swastika or burn a cross in this county, we will fine you, we will prosecute you, and if convicted you will go to jail," Simmons said.

On crime in general, Simmons said, "The real crime is that people aren't being told how bad it is getting. The projected rise in crime around new Metro stops will impact on the quality of life of the affected communities."