WARSAW, JULY 6 -- Prime Minister Tadeusz Mazowiecki today swept three former Communist ministers out of his cabinet, called for quick national elections and pleaded with the Polish people to reject populist promises of easy solutions to the country's severe economic ills.

Mazowiecki's speech before the Polish parliament -- his most impassioned defense of his nine-month-old government -- was an extended and acerbic rebuttal to months of criticism from Solidarity leader Lech Walesa.

Despite the prime minister's uncharacteristically blunt language, a number of the major policy changes announced today, including the ousting of former Communists from his cabinet and the call for elections, were direct concessions to Walesa and appeared designed to ease public pressure on his government.

Walesa, who picked Mazowiecki to lead the government last fall, has accused the Solidarity-led government of coddling Communists and betraying workers.

Walesa, the former shipyard electrician whose rebukes of the government echo frustrations of many economically squeezed Poles, has demanded that he be chosen by parliament as president.

One of Walesa's key advisers, Jaroslaw Kaczynski, dismissed the prime minister's speech today as "half-measures." He said Walesa would continue to campaign for president, as well as for the dismissal of all former Communists from the government and for the seizure of companies they still are running.

Although Mazowiecki never mentioned Walesa by name, the ministerial changes he announced, along with the combative tone of his words, left little doubt that he was defending himself and his policies of "evolution not revolution" from the populist demands of a man he used to call "Dear Lech."

"Standing in front of you and in front of the entire society, I must say clearly that I see danger on our peaceful road to democracy," said Mazowiecki.

"In the sphere of political life, the sense of responsibility for the country, for the state, is diminishing. Matter-of-fact arguments are being replaced by language of brutal struggle. An opponent who should be fought with arguments is treated as an enemy to be destroyed," the prime minister said.

Defending his government's economic reform program -- the most far-reaching in post-communist Eastern Europe -- Mazowiecki said that workers should not be deceived into thinking there is a simple or quick way of recovering from four decades of Communist misrule.

"I am saying this as a warning against looking for easy ways to prosperity," Mazowiecki said in a thinly veiled reference to Walesa's claims that reform should not mean severe hardship for workers.

"He who makes such promises will be destroying the indispensable conditions for economic recovery. Be it for party, group purposes or for individual ambition, {he who makes such promises} will shoulder responsibility for this country," Mazowiecki said.

The prime minister said a retreat from the country's free-market reforms would end Poland's chances of having part of its $42 billion debt forgiven by Western creditors. He said it also would mean that "foreign investors would turn their back on us."

"Investors are looking at Poland with big interest but also with growing concern over manifestations of instability," Mazowiecki said in another reference to Walesa's challenges.

In one of his most visible concessions to Walesa's criticisms, the prime minister dumped the two former Communists in charge of the country's police and army.

Communists were assured positions in the government last year as part of a deal by which Solidarity took power. The firings were intended to alert Poles that Mazowiecki no longer felt any need to treat former Communists with kid gloves.

In the cabinet changes, the best known of the ousted former Communists is Gen. Czeslaw Kiszczak, the interior minister. Kiszczak jailed thousands of Solidarity activists under martial law in the early 1980s. Also dismissed were Gen. Florian Siwicki, the defense minister since 1983, and Transport Minister Adam Wieladek.

In all, five ministers offered their resignations. One former Communist, Marcin Swiecicki, a respected technocrat who is minister of foreign trade, was retained on the cabinet.

{The parliament later Friday approved three of Mazowiecki's four proposed replacements, but rejected Artur Balazs, founder of the farmers' union, Rural Solidarity, as agriculture minister because of Peasant Party demands that the post go to their group, the Chicago Tribune reported.

{Solidarity activist Ewaryst Waligorski, nominated to run the transport ministry, Rear Adm. Piotr Kolodziejczyk, the defense ministry nominee, and Krzysztof Kozlowski, who was picked to move up from deputy interior minister to replace Kiszczak, were approved.}

Mazowiecki also announced that national elections -- expected to result in Walesa's winning of the presidency -- cannot be put off for long. The announcement amounted to an admission that Walesa's criticism has succeeded in undermining the legitimacy of the government.

"Poland cannot afford the legal validity of legislative and executive power to be questioned," said the prime minister, who until recently had insisted that elections would have to wait until next year. "I think that we cannot afford a many-months-long election campaign."

In another apparent response to criticism from Walesa, Mazowiecki said that the government would ease restrictions on wage increases, allocate additional money for housing, social welfare and health services and increase benefits to farmers.

Farmers are threatening to set up roadblocks around the country on Monday unless the government meets their demands for guaranteed prices and low-interest loans.

Mazowiecki today assured angry farmers -- who have held two strikes in recent weeks that were broken up by police -- that he does not "personally disfavor" them.

He said the government will try to meet their demands, but that they must understand the state has "limited possibilities."

In recent months, as economic reform has caused a sharp contraction in the economy and a 40 percent drop in living standards, strikes and threats of strikes have emerged as a major danger to Mazowiecki's government.

Walesa has proved that he is the only person in Poland with enough credibility among the rank and file to head off strikes peacefully. Influential advisers inside the government say Mazowiecki has concluded that the best way to use Walesa's immense populist power -- while blunting his capacity for gumming up the reform process -- is to quickly call an election that would make him president.