WARSAW, Poland (AP) _ Prime Minister Mieczyslaw F. Rakowski on Monday told the first meeting of his Cabinet that the new government begins its work ''in conditions of substantial disorder.''

''Only palpable, measurable effects of improvement can overcome the attitude of hopelessness in society,'' Rakowski said, according to a report by the PAP news agency.

It said Rakowski also declared that law and order must be maintained and accused anti-government protesters who demonstrated Sunday of trying to block planned talks between the communist authorities and the opposition.

Rakowski became prime minister Sept. 27 and his Cabinet was approved by the Sejm, or parliament, last Friday.

Polish television broadcast scenes of hundreds of pro-Solidarity demonstrators marching Sunday in the port city of Gdansk - birthplace of the now-outlawed independent trade union movement - and then demonstrators hurling stones at riot police.

Rakowski said: ''The government holds the opinion that the manifestations of political adventurism ... were provocations aimed at torpedoing national agreement,'' PAP reported.

Such incidents ''drastically disturb the atmosphere'' before the promised round-table discussions, he said, adding:

''The government discussed indispensable measures to counteract attempts at destabilizing the country and to enforce law and public order.''

Round-table talks that would include the topics of trade unions and political and economic reforms had been expected to begin this week, but disagreements over the way they would be conducted and who would participate have forced a delay, said Andrzej Stelmachowski, a mediator attempting to arrange the discussions.

The government has said Solidarity representatives would not be allowed to participate.

Other opposition leaders turned down offers to join the new government pending results of the talks, but PAP said Rakowski told his Cabinet the government would carry out reforms before the negotiations begin.

It reported he said restructuring the economy ''must be radicalized and accelerated,'' market supplies increased and price increases curbed.

Economic reform will mean that ''people who want to work better ... can count on increased incomes,'' he said.

Referring to strikes that shook Poland in May and August, Rakowski said, ''The sources of conflicts have not disappeared. Thus, the welfare of workers and all working people, their needs and perceptions, must remain at the center of the government's attention.''

Gen. Wojciech Jaruzelski, head of the communist party and Poland's top leader, attended the meeting and called the new Cabinet ''a government of great opportunity,'' according to PAP.

It reported the general spoke of ''various kinds of provocation'' but said authorities remain ''fully and deeply convinced about the necessity for reconciliation.''