Purpose This study aims to investigate the relationships between various frontline management (FLM) styles, human resource management system (HRM) system strength and employees' helping behaviours as a form of organisational citizenship behaviours (OCBs). The research also examines the moderating role of workgroup loyalty in the association between HRM system strength and employees' helping behaviours.

Design/methodology/approach The research uses survey data collected from 315 government workers in Malaysia. Structural equation modelling (SEM) was employed to test the hypothesised relationships.

Findings Two FLM styles, “policy enactor” and “employee coach,” positively predict employees' helping behaviour. However, the “organisational leader” FLM style did not significantly lead to employees' helping behaviour. HRM system strength significantly mediates the relationship between the three FLM styles and employee helping behaviours. Finally, workgroup loyalty significantly moderates the relationship between HRM system strength and employees’ helping behaviours as OCB.

Practical implications With a wealth of literature demonstrating the importance of FLMs in the implementation of HRM and a growing body of literature demonstrating the robust nature of the “system strength” argument, human resource (HR) practitioners are increasingly able to focus their attention on the way the system and FLMs contribute to employee outcomes and organisational performance. Our results indicate that HRM system strength does indeed enhance the impact of FLM styles on employee helping behaviours.

Originality/value The originality of this paper is that it acknowledges and empirically examines the heterogenous nature of FLM styles, through signalling theory in enacting HRM policies and links the growing FLM literature to the HRM system strength research. These concepts have also been tested for the first time in a Malaysian context.