Stockholm — Despite a crackdown by the Soviet authorities, a third half-hour protest strike by thousands of workers in the Baltic republic of Estonia will go ahead as planned Feb. 1.
Reports reaching Stockholm from dissident groups inside Estonia indicate that support for the action is growing because of discontent over increasing food shortages.
Ants Kippar, chairman of the Relief Center for Estonian Prisoners of Conscience, said resistance had hardened despite sackings and arrests of those taking part in the first two strikes, held Dec. 1 and Jan. 4.
''There is now a severe shortage of meat,'' he said. ''This and the continued Russification of Estonia have increased discontent this winter. And, of course, events in Poland have influenced the situation.''
He said that at least 150 people had been arrested in Tallinn, the Estonian capital, and that among those sacked for taking part in the Jan. 4 action was Dr. E. Roose, a surgeon at the Mustamaklinik hospital, near Tallinn.
''We do not know what has happened to Dr. Roose since his dismissal. We fear he has been arrested,'' said Mr. Kippar.
He said he knew personally of another four people under arrest in the central prison in Tallinn for taking part in the Jan. 4 strike.
The strikes have been called for in leaflets distributed throughout the Baltic states of Estonia, Lithuania, and Latvia, signed by ''The Democratic Front of the Soviet Union - NLDRR.''
The leaflets demand the recall of the Soviet Army from Afghanistan, an end of interference in Poland's internal affairs, the stopping of the export of food from the Baltic states to the rest of the Soviet Union, an end to ''discriminating forms of trade,'' the release of political prisoners, and an end to political banishment.
They also ask for military conscription to be reduced by six months and for adherence to the Helsinki Accord on human rights.
The leaflets call for a ''silent half-hour'' between 10:00 and 10:30 a.m. on the first working day of each month.
''All wheels will cease to move. Traffic will be halted. All movement and activity will cease - wherever we are: in our workplaces, at outdoor sites, or if we are on personal business, in town, in the country, in the fields,'' says the appeal.
''All streetcars, trolley buses, taxis, trains, and waiting rooms will empty. Streets and pavements will be devoid of pedestrians. The whole country will be paralyzed for 30 minutes.''
There is no evidence reaching Baltic exiles in Stockholm that Estonia has been ''paralyzed.'' Traffic has been reported moving freely, but there has been considerable support for the strikes, which have become almost an institution for dissatisfied Estonians.
The exile groups say support for the strikes has been more widespread among Estonians than is readily apparent. This is because there are now 250,000 Russian immigrants in Tallinn, outnumbering the 220,000 Estonian residents. ''Most of the Russians are working normally,'' Mr. Kippar said.
Discontent over Russian immigration has been growing rapidly. Last year violence flared at a basketball game between Estonia and Russia in Tallinn. Several policemen were injured and dozens of arrests were made.
Earlier, Estonian schoolchildren had protested at being forced to learn Russian.
The strike leaflets warn against civil disorder and ''outbreaks of nationalism,'' however.
Heiki Ahonen, a youthful Estonian dissident, is believed to have been badly beaten by the police in Tallinn after being arrested distributing the leaflets, and two other dissidents, Kalju Metk and Artem Yusevych, are known to have been interrogated by the Soviet KGB.
Reports reaching Sweden indicated that support for the strikes is strongest in Estonia but that there have been sporadic actions in Latvia and Lithuania.
Mr. Kippar said he had regular telephone contact with dissidents inside Estonia. ''It is a completely new organization that is behind the present strikes,'' he said.