The federal Senate estimates hearings have commenced in Canberra, marking the start of a two-week period in which senior public servants are questioned in detail about the operations and decisions of their departments.

The opening day focuses on the Department of Parliamentary Services (DPS) and the Department of Climate Change, alongside other agencies appearing throughout the evening session.

Department of Parliamentary Services secretary Jaala Hinchcliffe is appearing for the fourth time in her role, continuing to face scrutiny over several controversial matters within the agency.

These include questions surrounding the sudden termination of her predecessor and a contentious decision to provide tens of thousands of sensitive communications to a third party without the appropriate security clearance.These issues are expected to remain central topics of questioning as senators examine governance and accountability within the department.

Climate change department secretary Mike Kaiser is also set to appear, with the Coalition signalling it intends to challenge and potentially dismantle aspects of Labor’s climate change administrative framework.As a result, questioning is expected to focus on the structure, cost, and purpose of the department’s programs and policy delivery.

Later in the evening, representatives from the Royal Commission on Antisemitism and Social Cohesion are due to appear, alongside Agriculture department secretary Victoria Anderson, who is attending her second estimates hearing in the role.

Senate estimates hearings are a key accountability mechanism in Australia’s parliamentary system, allowing senators to scrutinise public spending, policy implementation, and departmental decision-making across the federal public service.