BASICALLY iNDUSTRIAL RELATIONS IS the relationship between the employer and employee & employee and aemployee so all these are Humanbeings ie employees. The HRD / HRM's basick activcity and responsibility is to take care of Human related matters in this context HR has to play a major role in industrial relations.
Until and unless there is cordial / congenial atmosphere exists in the organization no HR processes can take place hence the basic responsibility is to ensure a good / cordial relationship in the organization. To take forward the HR processes and initiatives the HR has to ensure a healthy atmosphere in the organization. In my opinion the HR has to ensure a cordial relationship / atmosphere in the organization. Hence it is the basic responsibility of the HR, if the Head of HR don't have the quality then he has to recruit an IR specialist in his team and lead.
Thanks and regards - kamesh