PRAGUE, Czechoslovakia (AP) _ About 4,000 East Germans were jammed into the West German Embassy in Prague today with new arrivals pouring in each hour, all eager to emigrate West despite promises of reform from their Communist leaders.

''It's just the same hardheaded idiots as before,'' said a bricklayer from Karl-Marx-Stadt. ''What's going to change? The corrupted socialism in our country is just getting new clothes, that's all.''

''I don't believe that anything will change there,'' said another young man. ''The reforms are only for the outside world.''

Red Cross workers and refugees unloaed tents and bedding trucked in from West Germany.

East Germany has agreed to let its citizens here renounce their citizenship and then go to West Germany, where they are automatically granted citizenship.

But with East German diplomats processing only about 100 applications a day, it was feared the embassy and its gardens, which have a capacity of about 5,500 people, would be overflowing by the weekend when a rush of new arrivals was expected.

Embassy sources, who put the number of East Germans at about 4,000 just before noon, said negotiations were under way with Czechoslovak authorities for more space.

Some people arriving today said the roads to Prague were crammed with East German cars.

The wave began Wednesday after East Germany's new leader, Egon Krenz, lifted a month-old travel ban to Czechoslovakia, the only country East Germans can visit freely. Krenz's predecessor, Erich Honecker, had imposed the ban to stop an earlier exodus of East Germans to the West German Embassy in Prague.

The exodus has mainly involved skilled workers in their early 20s and 30s. At least 200 to 300 children played inside the embassy grounds.

Those who have left East Germany include at least 1,100 doctors and nurses, and this has severely strained health services in the Communist country, an East German health officials said today.

Dr. Geerd Dellas, the health administrator for the city of East Berlin, said doctors and nurses from exclusive clinics serving high-ranking Communist officials have been drafted to work in ordinary hospitals. Nurses still in school who were near graduation have also been employed, Dellas said.

East Germans were swift to take advantage of the lifting of the travel ban. Eight thousand crossed into Czechoslovakia in the first 24 hours, and the number in the West German Embassy swelled from 2,100 Thursday night to some 4,000 by noon today.

''You've just got to use an open barn door to the West while you can,'' said one 25-year-old from Leipzig.

Most refugees simply walked in through the giant wooden doors of the Palais Lobkowicz, the elegant Baroque palace that houses the West German Embassy in Prague's ancient Mala Strana district.

A Czech policeman outside the embassy said he and his colleagues had orders not to interfere because it was a matter for the two Germanys alone.

The West German government appealed to East Germany to speed up the bureaucratic process for the East Germans in Prague and about 700 still waiting at the West German mission in Warsaw, Poland.

East Germany said it was working as fast as possible and reiterated that it would be better for its citizens to apply for legal emigration.

East Germans complain that it often takes years for a such requests to be granted.

Since August, more than 70,000 East Germans have fled their homeland through Hungary and Bonn's embassies in Prague and Warsaw.

On Oct. 3, Honecker banned travel to Czechoslovakia to try to halt the exodus of young, skilled workers badly needed in his labor-intensive economy.

But the exodus and pressure for reform led to Honecker's ouster Oct. 18. He was replaced by Krenz, who is trying to bolster the Communist Party's sagging authority with promises of reform and foreign travel.

Krenz faces mounting pressure for democratic reform in East Germany, where tens of thousands have repeatedly taken to the streets to press for more democracy.

Returning from Poland on Thursday, Krenz urged closer economic ties to the West. Several top Communist officials resigned, including Honecker's wife, Margot, as education minister.