Nippon Telegraph and Telephone Corp. has struck a deal during labor-management negotiations to restrict wage increases for employees in their 40s and 50s next year, so the firm can set aside money for postretirement jobs, sources said Saturday.

The agreement was reached in light of a revised law that will take effect next spring, requiring companies to retain their employees until the age of 65, if they choose to continue working instead of retiring at age 60.

The new wage measure will apply from next autumn to around 180,000 employees at eight companies under the telecom giant, including NTT DoCoMo Inc. and NTT Data Corp., according to the sources.

Given the magnitude of the NTT group's total workforce, some corporate officials said the change could affect other domestic companies seeking ways to cope with the new mandatory employment system, which will mandate them to continue employing those who wish to keep working until age 65.