The government yesterday ended federal subsidies for about 150,000 workers whose "temporary" public service jobs had turned into more or less permanent positions.

There was no immediate estimate of how many of the 150,000 would actually go unemployed as a result of the congressionally mandated cutoff. New York City officials estimated that at least 14,000 would be laid off in that city alone.

Thousands are being absorbed into city, state or county payrolls and others have been placed in private sector jobs, according to officials around the country.

In some areas, it appeared that the long-planned fund cutoff achieved the desired result of prodding local governments into providing unsubsidized permanent jobs.

About 600,000 low-income Americans are currently employed in public service jobs under the Comprehensive Employment Training Act. In theory, the jobs were intended as a bridge to permanent employment in the public or private sector. But there was no time limit on CETA employment until last year when Congress imposed a 78-week limit on the jobs.

Those persons terminated yesterday had held their jobs more than 78 weeks-- some as long as four or five years.

"Part of the problem is that these jobs dragged on for a long, long time and people became comfortable in them," said a spokesman for the U.S. Conference of Mayors.

"I'm sure it came as a shock for some to be reminded that these are not permanent positions," added David Cohen, an aide to Chicago Mayor Jane Byrne. "Some of them, who had been there four or five years, are not at all happy."

Cohen acknowledged, however, that the city is now "doing a more thorough job" of finding non-subsidized jobs than it was before the fund cut off was mandated. Of 6,500 public service employes whose subsidies expired yesterday, all but 2,400 have been accounted for with other jobs, Cohen said.

Cohen said Chicago officials embarked on a major effort at placement last spring in cooperation with local businessmen and community organizations. Such activities were 'much softer" before Congress set the limit, he said.

Originally, about 200,000 people were to have lost subsidies yesterday. Under the law, however, about 50,000 received temporary waivers because of high unemployment rates or other problems, federal officials said.