Gen. Wojciech Jaruzelski has discarded his uniform for subdued civilian suits. "Solidarity" and "martial law" have been eliminated from the vocabulary of official speeches. A release of political prisoners is being carried out without fanfare, and government texts are dominated by plans for the economy.

With the inauguration of a new government and legislature this month, the communist authorities seem determined to convince both the nation and foreign observers to the East and West that their long crisis is finally under control. Yet behind the official confidence lie continuing concerns about internal opposition, chilly foreign relations and a dangerously weak economy.

"What was most dramatic is behind us and what is most difficult is before us," the government daily Rzeczpospolita quoted Jaruzelski Friday as saying. It added: "The government will badly need the support of all creative social forces."

Almost four years after its declaration of martial law and suppression of the Solidarity union, Jaruzelski's administration has achieved its most basic objective of quelling active internal resistance. Street demonstrations have been infrequent and easily controlled in the last year, and an attempt by Solidarity's underground leadership to mount a strike last summer failed.

By almost every other measure, however, Jaruzelski has failed to eliminate the political and economic challenges that continue to set Poland apart from the rest of Eastern Europe -- and clearly displease its Soviet allies. Although ousted from the streets, an opposition political underground spans the country and includes tens of thousands of activists who sustain a formidable parallel culture of independent literature, art, education and factory-level labor agitation.

Efforts by authorities to repress this network, while producing few substantial results, have had the effect of continuing Poland's estrangement from western governments and needed western credits. The powerful Roman Catholic Church has shielded many of the independent movements while rebuffing government efforts to win or force its collaboration.

Jaruzelski's efforts to rebuild crippled industry and living standards are in danger of unraveling. Industrial production and western trade have both slumped alarmingly this year, and outsized wage increases, forced in part by pressure from workers, have defeated official efforts to stabilize the internal marketplace. The official media and even a report approved by the Sejm, or legislature, contend that a key program to introduce market-oriented economic reforms has broken down.

Perhaps most troubling for the authorities, opinion polls suggest that the majority of Poles, while not actively resisting communist rule, remain demoralized and suspicious of the government, while up to a quarter of the population is in opposition.

Recent elections produced only a slightly higher turnout, by official accounts, than in June 1984. A substantial majority of voters did not bother to mark ballots despite a nominal choice of candidates.

"The great failure of the government is that four years after martial law and despite all the measures, there is still at least 20 percent of the people who are politically conscious and actively working against the authorities," said an opposition journalist. "And that means constant trouble." In this context, Jaruzelski's recently completed reorganization of the party, government and Sejm leadership and accompanying outline of new policies strike many obsevers here as unimaginative and tightly constrained.

The 62-year-old general, say diplomats and political activists, clearly consolidated his own position within the communist Polish United People's Party and strengthened his control over policies by installing nine new Cabinet ministers and ousting a leading hard-line opponent from the party Politburo.

The new government leadership includes no strong new figures or technocratic experts who might revive flagging initiatives, however, and the few new policy steps have been subdued and cautious.

A new official strategy for winning over opponents, for example, has seemed to emerge in the authorization of a new and nominally independent group, called Consensus, to "promote dialogue" among the government, church and moderate opposition. Yet authorities have stressed a continuing hard-line approach toward Solidarity leaders, activist priests, and others perceived as unreconciliable opponents.

Major speeches delivered in the last two weeks by Jaruzelski and the new premier, Zbigniew Messner, suggest action in the coming months to revitalize the three-year-old program of economic reform and neutralize resistance to it in the party and bureaucracy.

Although citing the economy as the key to the political situation, government officials admit that they will have little to offer Poles in terms of improved living standards for the forseeable future, even if their policies succeed. Economic indicators remain well below those of the late 1970s and official plans call for increases in consumption barely above population growth.