Supporters of Poland's independent trade federation, Solidarity, clashed with police for the second day today amid increasing industrial unrest over food shortages and price rises.

Meanwhile, Solidarity's leader, Lech Walesa, met with the Roman Catholic primate of Poland, Archbishop Jozef Glemp, in what could be an attempt to defuse tension here. Glemp briefed Walesa on his talks in Rome last week with Polish-born Pope John Paul II.

Earlier, Walesa's return to Poland from France had been delayed several hours because of a Paris airport strike organized by one of the unions that sponsored his trip.

The latest incident took place in the southwestern industrial town of Wroclaw, where a crowd of 1,500 marched on police headquarters following the arrest of four Solidarity activists for reading union bulletins. Police later cordoned off the area, and the official Polish press agency PAP said public gatherings had been banned in the town.

Local Solidarity officials said the town was quiet and the union would be meeting in the morning to decide on future action. One activist, a 16-year-old boy who had been helping broadcast slogans from a van, was later released.

Yesterday, police fired tear gas at a crowd of 5,000 Solidarity supporters in the southern city of Katowice following a similar detainment incident. But today the city center was reported calm and the union resumed the sale of leaflets and bulletins.

That incident coincided with a wave of industrial unrest as workers in at least 10 of Poland's 49 regions either struck or prepared to strike to protest food shortages and price rises. Solidarity leaders meeting in the Baltic port of Gdansk will debate the possibility of a nationwide "warning" strikeThursday.

They are also expected to formulate a response to the new, tougher line adopted by the communist authorities.

The clashes between Solidarity supporters and police in Katowice were seen here as the kind of incident that may become more frequent should the government crack down on union activities.

The trouble began when police attempted to arrest Solidarity activists distributing union publications from a van decorated with the slogan "Freedom for political prisoners." The crowd chased the police, who replied with tear gas. The crowd then overturned a police van and threw stones at a police building.

Here, too, police released an activist they had arrested.

During the past six months a couple of similar incidents have taken place, starting when a small police station outside Warsaw was burned down last April after a quarrel over cigarettes. Last month there were more serious riots in the western town of Konin when police were unable to prevent clashes between residents and gypsies.

In all cases, Solidarity officials have tried to contain the anger of the crowd. In Katowice yesterday, the riot police withdrew after the clashes and the workers' militia kept order during the night.

A common fear here is that some relatively minor incident could flare up into major disturbances as winter approaches and the economy deteriorates. The mood of ordinary people forced to wait in line for hours for everything from meat to detergent is becoming more brittle and impatient.

So far, however, both the government and Solidarity appear capable of defusing such incidents before they get out of control.

The police reaction in Katowice yesterday seems to suggest that the authorities were taken off guard by the reaction of the crowd. Similar attempts to confiscate union publications have been under way for some weeks and are regarded as part of a normal cat-and-mouse game.

For their part, local Solidarity officials denied police allegations that the activists were engaged in distributing "anti-Soviet" and "antistate" material. They also dismissed suggestions that the action was connected with the resignation of Stanislaw Kania as Communist Party leader and his replacement by Gen. Wojciech Jaruzelski.

Despite the tougher rhetoric emerging from recent party meetings, and an intraparty debate over the feasibility of declaring a state of emergency, there is no evidence that the authorities are preparing actively for a violent crackdown on Solidarity in the near future.

Their strategy at present appears to involve a combination of an intensified propaganda campaign against "antisocialist" forces in the union, a refusal to give way to what are regarded as unjustified demands and the use of legal weapons against the union's uncensored publications.