Forestry owners will run special Government-funded safety seminars in the New Year, but unions are blocked from attending them.
The safety seminars are being paid for by the Ministry of Business, Innovation & Employment, but the Council of Trade Unions says an offer to include a leaflet from the union advising workers of their rights has been rejected.
CTU president Helen Kelly said the offer was not a political gesture, but was to inform workers about the impact of poor working conditions on safety.
The CTU has highlighted several incidents of worker fatigue recently and wants union members to know they can refuse to work unreasonable hours and in dangerous situations.
Ms Kelly said it's not right that unions are locked out of important safety meetings.