Newspaper Agency Corp., the production, advertising and circulation arm of the Deseret News and The Salt Lake Tribune, will reduce its work force by 6-12 percent in early 1989 due to a drop in advertising revenues and increases in expenses, particularly newsprint costs.

NAC President Dominic Welch said the companywide reduction will be accomplished by consolidation of jobs, elimination of duplication of work in various departments and reassignment of work among various jobs."In order to ease the impact of this reduction," said Welch in a letter to employees, "and to encourage (that) this reduction take place by attrition (retirement) rather than by termination in so far as possible, a voluntary early retirement incentive has been developed and is being offered to eligible employees."

Welch said the incentive will be offered to all NAC employees who reached age 55 by Jan. 1, 1989, and whose age and years of service added together total at least 70.

He said eligible employees will receive a letter within the next few days detailing the incentive offer.