In a remarkably frank assessment of 10 years of effort to build socialism in Tanzania, President Julius Nyerere has concluded that his country is certainly neither socialist nor self-reliant" and that the goal of making it to "is not even in sight."

But he also asserts that Tanzania has taken "very important steps" toward becoming a socialist state and that the Tanzanian "national ethic" is socialism.

The 51-page document, called "The Arusha Declaration Ten Years After," a probably the most honest self-critism of a government's performance by any African leader still in power. Written in January, it has just recently gone on sale and been distributed to all government and party offices for study and discussion.

The Arusha Declaration, named after the town in northern Tanzania where it was adopted in January 1967, first spelled out Tanzania's commitment to a socialist policy. It has provided the ruling party, the Targanyika African National Union (TANU), with its guiding ideology and program of Ujamaa or communal villages. The party was recently renamed Revolutionary Party.

The Tanazanian experiment with socialism has generated more comment, studies and controversy over its success or failure than probably any other African attempt to follow a socialist path. Nyerere himself has greatly encouraged teh debate by allowing outside scholars and his own people to freely criticize and write about the experiment.

He has also gained a large amount of international financial support for his experiment with socialism. Tanzania receives about $300 million annually in foreign aid, one-third from the World Bank and another third from the Scandinavian countries. The rest comes from a variety of Communist and capitalist states, including China, the Soviet Union and the United States.

Critics of Tanzanian socialism probably will read the report as a confirmation of their contention that it is largely bankrupt and its supporters as evidence of their belief that it has been moderately successful. Thus Nyerere's report is certain to be of intense interest to scholars, development experts and governments.

"Ten years after the Arusha Declaration," wrote the gray-haired Tanzanian leader, known as walirau (teacher), "Tanzania is certainly neither socialist nor self-reliant. The nature of exploitation has changed but it has not been altogether eliminated. There are still great inequalities between citizens. Our democracy is imperfect. A life of poverty is still the experience of the majority of our citizens."

Furthermore, he said, "our nation is still economically dependent upon the vaguries of the weather and upon economic and political decisions taken by other peoples without our participation or consent.

But Nyerere was not discouraged by the failings, saying that the fact Tanzania was not yet socialist was "neither surprising nor alarming. No country in the world is yet fully socialist, although many committed themselves to this philosophy decades before Tanzania even became independent."

He made both positive and negative assessments of his country's performance.

"First and foremost," he haid, "we in Tanzania have stopped and reversed a national drift toward the growth of a class society based on ever-increasing inequality and the exploitation of the majority for the benefit of a few.

"We have changed the direction of our national development so that our national resources are now being deliberately directed toward the needs of this nation and its people."

Secondly, Nyerere wrote, Tanzania has established "some of the attitudes which are necessary to the development of socialism. . . . The argument now is not on the principle but on how, and how fast, we can move" toward socialism.

The Tanzanian leader also listed other successes.

The nation, he said, had made "reasonable good progress" toward providing the country's 14 million people with basic health, education and transportation facilities, particularly in education. Virtually the entire population, he said, had been resettled, into 7,684 villages which could receive government service.

The country also had established public institutions needed to establish Tanzanian control over the economy, such as state-run banks and semi-governmental companies.

There also had been a trebling of the value of industrial production and a nearly tenfold increase in government spending on agricultural development.

Other achievements included a reduction in the dispairty between the highest and lowest incomes in the public sector from 20-to-1 to 9-to-1, and greater direct participation in local government through administrative decentralization and the Ujaam campaign.

Nyerere also discussed what he regards as the country's shortcomings. Chief, he said, was the government's dependence on foreign aid and deficit financing for development and its failure to take seriously its own doctrine of self-reliance.

"The fact is that we are still thinking in terms of 'international standards' instead of what we can afford and what we can do ourselves," he said. "The present widespread addiction to cement and tin roofs is a kind of mental paralysis . . . People refuse to build a house of burnt bricks and tiles: They insist on waiting for a tin roof and 'European soil' [cement]."

Another major failing was "only a neglible real improvement" in the "per capita standard of living."

Nyerere also was concerned that the government had become the fastest growing sector of the economy, and that food production had not kept pace with population growth. Also, he said, "All too often leaders in the government and the civil service - and even in the party - fail to show by their actions that they care for the people."

"The leaders of Tanzania must accept that democracy is at the heart of socialism," Nyerere said. "Leadership by intimidation is not leadership."

The Tanzanian leader ended his report with a warning of "very difficult" economic problems for the next three to four years and a call for a major effort to increase production and to take more seriously the need for national self-reliance. "There is a time for planting and a time for harvesting," he said. "I am afraid for us it is still a time for planting.