Nicaragua's Sandinista government has virtually eliminated extreme human rights abuses such as torture and summary execution that were trademarks of the final years of the Somoza dictatorship but has placed unjustificable limits on political, press and judicial rights, according to the Inter-American Commission on Human Rights.

In a report released yesterday, two years after the leftist Sandinistas ousted former president Anastasio Somoza following a civil war, the commission repeatedly notes that the former guerrillas took over a country in "a situation of misgovernment and anarchy" that "lacked any public administration, police and administration of justice."

"Resolving the problem of a lack of services and public servants was undoubtedly one of the most difficult and delicate tasks that the revolutionary government had to deal with," the 171-page report says.

The commission judgment on how the Sandinistas have dealth with that problem is likely to provide fuel for both sides of an ongoing debate in this country and in Nicaragua between those who say the new government is a vast improvement over the old and should be given more time to find its way, and those who maintain that it is firmly entrenched in the Soviet orbit.

The report is based on a 10-day visit to Nicaragua last October -- nearly two years from the time the commission went there when Somoza ruled. Following the earlier investigation by the seven-man body of representatives from Organization of American States members, the commission charged Somoza with "grave, persistent and widespread" rights violations during and after a September 1978 Sandinista-led insurrection, including "indiscriminate bombing of civilians," torture and "summary mass executions" of civilians.

Last year's visit, which was followed up with additional documentation until last month, found little evidence of such extreme violations. Although it strongly criticizes the Sandinistas for what it says were a number of summary executions, particularly at a military garrison called La Polvora outside the southern city of Granada, it notes that such events occurred almost exclusively between July 19 and July 29, "during the weeks immediately subsequent to the revolutionary triumph, when the government was not in effective control of the public power."

Still, the report says, "these have not been investigated and those responsible have not been punished."

Although it documents several cases of abuse of prisoners bordering on torture, the report says that "in general . . . torture is not practiced in Nicaraguan jails [and] . . . even when incidents of this nature do occur, they are not authorized by higher authorities."

But the commission was highly critical of other forms of treatment accorded prisoners, including severely substandard prison conditions marked by overcrowding, sanitary, medical and recreational facilities that are limited or nonexistent and insufficient and inedible food.

A footnote to this section of the report mentions an ongoing commission investigation of reports received at press time concerning the deaths last month of 16 prisoners who were killed by Sandinista soldiers while allegedly trying to escape.

The commission criticizes the "special tribunals," established outside the normal judicial system to try soldiers of Somoza's National Guard and those deemed to have had close ties for the former government.

"Irregularities" in the special courts, the report says, included "vagueness and imprecision of many of the allegations or charges," inadequate time -- in most cases 24 hours -- to prepare a defense, and a "lack of findings to support the conclusions of the sentences."

During the three-month existence of the tribunals, according to figures provided the commission by the government, 1,760 prisoners were released either by pardons or dismissal of charges. More than 200 were acquitted, and 4,331 were given sentences ranging from less than five years to 30 years, the maximum penalty under law.

In its closing section, the report recommends that all those sentenced to less than five years be considered for pardon, that the elderly and infirm be released and that all other sentences be reconsidered by the regular judicial authorities.

The report also criticizes laws and decrees limiting political and press activity as vague and subject to abuse. It documents cases of what one source close to the commission called "regular harassment" of opposition politicians, the country's opposition newspaper and the local human rights commission, a frequent critic of Sandinista policy.

In each of three documented cases concerning press freedom, the report found that government actions, ranging from censorship to arrest of journalists, were unjustified.

It calls on the government, which has banned electoral campaigning and postponed elections until 1985, to "assure the effective exercise of political rights of all citizens so that circumstances can be created that will permit general elections to be held within a short and reasonable period of time."

The commission also issued a report on human rights in Colombia based on the findings of observers sent there after the seizure of 16 diplomatic hostages in the Dominican Embassy in Bogota by the M19 guerrilla group early last year. The commission participated in the negotiations that ended with the payment of a large ransom and the release of the hostages two months after the attack.

As part of the agreement that ended the siege, the commission agreed to study the observance of human rights in Colombia, and particularly the military trials of imprisoned guerrillas.

The commission concluded that a number of prisoners have been killed while in custody of the police and military and many more have been tortured. It called on the government to end a state of siege now almost continuously in force for more than 30 years and criticized growing militarization of judicial procedures in Colombia.

The report also said that military operations against the antigovernment guerrillas in rural areas "have led to harmful excess against the local people" and "displacement of citizens" in the countryside.

The commission reported that Colombia, a civilian democracy, had a good record in guaranteeing freedom of religion and expression and opportunities for citizens to participate in the political process.