Labour Minister Frank Corbett says changes to the Workers' Compensation Act would affect more than 100 women.
Legislation was changed in 1999 so that remarried women would continue to receive their survivors' benefits, retroactive to the date when they remarried.
However, benefits for women who remarried before 1985 were only retroactive to 1999.
Corbett credited Betty Baumann of Glace Bay, whose husband died in a coal mine in 1960, for leading a group of widows who fought for the change.
The government says most of the compensation will come from the Workers' Compensation Board's accident fund, which covers workers injured on the job.
Self-insured employers, such as the provincial government, would be responsible for their portion of the cost.