The Engineering, Printing and Manufacturing Union is worried the mining industry will try to undermine attempts to set up a strong system of check inspectors at the country's underground mines.
The Royal Commission of Inquiry into Pike River mine disaster recommended that check inspectors - be reinstated at the country's mines.
They are are workers' representatives who have the power to shut down a mine on safety grounds.
The Government has said it will adopt the recommendation.
A paper obtained by Radio New Zealand under the Official Information Act reveals in July 2009 - about 16 months before 29 men died at Pike River - the then Department of Labour recommended against having check inspectors because companies opposed the idea.
The EPMU, which represents miners, will hold talks with officials from the Ministry of Business, Innovation and Employment this week about what regulation should be put in place to back up check inspectors.
Assistant national secretary Ged O'Connell said the mining industry opposed check inspectors in the past and he is not sure its view has changed.
But the chief executive of industry organisation Straterra, Chris Baker, said it is more relaxed about the matter now.
A spokesperson for Acting Minister of Labour Chris Finlayson said the Government had accepted all the recommendations of the Royal Commission and made implementing them a priority.