The expectation that the Australian Public Service (APS) is an ethical, values-driven institution providing impartial advice to ministers while acting in the public interest is enduring, and under a Westminster framework is fundamental to democracy. However, a more politicised public service resulting from public service reforms has challenged this notion in practice. While the principles and functions of the APS have been clearly set out in the Public Service Act and the Public Service Values, the informal concept of 'frank and fearless advice' is still regarded as a powerful term of reference by public servants and the general public. However, during the Howard government's term of office between 1996-2007, several incidents that generated claims of politicisation raised concerns about the lack of frank and fearless policy advice expressed in practice by the APS. Public sector reform undertaken since the 1970s has had a crucial impact on the way the public service is structured, and therefore has had a significant impact on the policy-making role of the APS and the ability of the public service to solve or even manage wicked problems such as social and environmental issues. The primary aim of this thesis is to gain some insight into the concept of the politicisation of the APS in order to identify its effect on social and environmental issues. From an historical institutionalist perspective, and using critical analysis with interviews as secondary research, this thesis focuses on the possibility of the politicisation of public service advice for wicked problems such as social and environmental issues that were often placed as secondary to the focus of the Howard government on economic and security issues. Two case studies have been analysed in this thesis; poverty as a social issue and water as an environmental issue. It is concluded that an enduring problem with both poverty and water are political priorities, which are difficult to change. Notwithstanding political considerations, the necessity for an apolitical public service is essential in contemporary Australia in order to ensure the public interest, equity and continued democracy when providing policy advice to government.