A part-time employee is an employee whose normal hours of work (averaged over a reference period of not less than seven days nor more than 12 months) are less than the normal hours of work of a comparable employee in relation to him/her. In respect of their conditions of employment, part-time workers are protected from being treated less favourably than full-time workers simply because they are part-time. Conditions of employment are defined to include all terms and conditions of an employment contract, whether statutory or otherwise, including for example: remuneration, pensions, voluntary health contributions, entitlement to sick pay, etc. Common instances where employers treat part-time employees less favourably would be where an employer selects only part-time employees for redundancy and also in terms of the proportion of annual leave granted to a part-time employee as compared to a full-time employee.

Less favourable treatment in relation to any pension scheme or pension arrangement is specifically permitted by the legislation where the part-time employee works less than 20% of the normal working hours of a comparable full time employee.