The New York Times management has issued a warning to some union workers here. Asserting that The Times must keep advertising rates in the suburbs low enough to reman competitive with burgeoning dailies there, publisher Arthur Ochs Sulzberger said production costs must be kept down.

In particular, The Times Co. chairman and president said the pressmen's union has been told that when its contract expires at the end of next March, there will be "no new agreement" without a reduction in manning requirements, which he said are 50 per cent higher for The Times than at suburban dailies.

And because the overall Times Co. is in good financial health, the paper's future would not be threatened by a strike today.

A confrontation over the pressmen's manning rules at The Washington Post led to a strike against the Washington paper in late 1975, which was settled some five months later when the Post Co. replaced most of the striking pressmen.

Sulzberger expressed confidence an agreement can be reached in the months remaining before the pressmen's contract expires.

We've go to do it," Sulzberger said, adding that management at the Daily News has agreed to a similar approach. Both papers are working together because "we both concluded that we must trust each other," he asserted.

He also took out a handwritten chart, showing the number of pressmen on typical Times units compared with newspapers "A. B. C and D." in the suburbs. On an eight-unit press for example, current union rules at The Times require 26 workers compared with 8, 11, 14 and 13 at the rival, suburban dailies.

Labor employment at the newspaper will continue to be reduced by attrition at least through 1980, according to company officers, with a consequent improvement in profit margins. The attrition rate in the pressroom is projected at 3.5 per cent through 1980 and overall pressroom manning is to be cut by a third, eventually.

Adds columnist James Reston: "If we were confronted now with the kind of problem (The Washington Post) had with the pressmen and we had to go down, we would not have to take an economic strike that would in any way jeopardize the life of the paper because the outside publications could carry it indefinitely."

Other publications of the Times Co. and a single TV station in Memphis make more money than the newspaper he said, referring to acquisitions by the parent company in the past decade. "That was a real spare tire".

The last Times-union struggle came in 1973, when the company stood firm in talks with printers and the union approved gradual automation of many jobs of exchange for lifetime guarantees of jobs for union members at that time. A 1970 agreement with the printers was described as disastrous - providing for 42 per cent wage increases over three years at a time the paper's profits began to sink.