Managua, Nicaragua — Critics of the Nicaraguan government here view new Sandinista concessions and offers to negotiate as ''cosmetic'' and ''superficial.'' These critics - ranging from the Roman Catholic Church and opposition political parties to the independent newspaper La Prensa and the business community - charge that the overtures do not foreshadow any change in what they see as the Sandinistas' goal of constructing a one-party, Cuban-style government.
According to observers here, the Sandinistas' recent concessions have been made to remove any pretext for a United States invasion of Nicaragua and in response to mounting criticism of the Sandinista government by some countries in Western Europe and Latin America.
The steps taken include:
* Sending home large numbers of Cuban advisers, from a total as high as 8,000 by some Western estimates.
* Asking Salvadorean guerrilla leaders to leave the country.
* Easing censorship of the opposition newspaper La Prensa.
* Promising to announce a schedule for elections.
* Approaching the private business sector, Roman Catholic Church hierarchy, and opposition political leaders to discuss differences.
But the chief reaction from critics within Nicaragua is skepticism.
Not one of the opposition politicians interviewed here feels the Sandinistas are sincerely trying to include them in the power structure.
''Our censorship is slightly less severe,'' says Pedro Joaquin Chamorro, the editor of La Prensa, ''but it is still very heavy. We do not want concessions from the Sandinistas, but liberty. We want fundamental changes in the governmental structure to include and tolerate all elements of the society. Until we are allowed to exist as in independent organization, and not gagged and controlled by the Sandinistas, we have nothing.'' Mr. Chamorro says the closing of his newspaper by the government is ''imminent.'' He claims the Sandinistas make it difficult for him to buy newsprint and have jailed some of his reporters.
Political opposition and Roman Catholic leaders here claim efforts to negotiate have been fruitless.
''When we meet with the Sandinistas, we get rhetoric, not dialogue,'' says one opposition party leader. ''We are vilified as counterrevolutionaries and traitors.''
A meeting last week called by the Sandinista-dominated Council of State to negotiate with opposition party leaders was boycotted by the independent groups.
Another meeting between the Sandinistas and the Social Christian Party, held to discuss arrangements for elections, ended with the Sandinistas attacking the party for wanting a return to the era of dictator Antonio Somoza Debayle.
Catholic Church leaders are also skeptical about the overtures. ''From all we can see,''says Msgr. Bismark Carvallo, spokesperson for the Catholic archbishop's office, ''the Sandinistas have not deviated from their agenda of splitting the Roman Catholic Church into two camps - those that are ideologically in tune with the Sandinistas and those that are not.''
Private businessmen say the Sandinistas have promised them special certificates guaranteeing the safety of their property from government confiscation for 25 years. The Sandinistas have also offered to meet with the president of the Superior Council of Private Enterprise (COSEP), Enriques Bolanos.
''When the Sandinistas came to power, they had our support,'' says a leading businessman and member of COSEP member.
''But once installed in the government they turned on private enterprise and reneged on their promises of a mixed economy. They are Marxist ideologues who desire total control. They have ignored their pledges to us in the past. Weufnjump,15pCOOL30COOL28ufmrk,47lwould be very foolish to believe in theirsincerity now.''
The business community has asked that any agreement with the Sandinistas be negotiated by the four countries in the Contadora group - Panama, Mexico, Colombia, and Venezuela. But the Sandinistas have refused any inclusion of the Contadora group in talks. The government says that the friction is an internal matter and does not concern neighboring countries.
The Sandinista leadership refers daily to what it claim is an imminent United States invasion of their country. The government-controlled television stations and two pro-Sandinista newspapers devote large amounts of space to defense preparations and clashes between Army troops and the US-backed guerrillas.
The removal of Salvadorean guerrilla leaders and thousands of the Cuban schoolteachers, economists, and others working in the Sandinista government is seen here as an effort by Nicaragua's leaders to defuse charges that they have become closely tied to Cuba and other armed rebel groups in the region. Western diplomatic sources says about 8,000 Cubans have been working in Nicaragua.
''The Sandinistas,'' one observer here says, ''saw the Reagan administration use these two charges to justify the invasion of Grenada. They want to take away as many pretexts for invasion as possible to muster international support.''
Daniel Ortega Saavedra, coordinator of the ruling junta, announced recently that the Nicaraguan government was prepared to send all foreign adivsers home and stop buying arms abroad if other countries in the region would do the same.
But given the massive military involvement by the United States in El Salvador, observers do not expect the Reagan administration will ever agree to the Ortega proposal.