The relationship between budget offices and line ministries is evolving across OECD countries. Effective budgeting now depends on strong internal finance functions within line ministries, collaborative engagement across the budget cycle, and sustained investment in skills and systems. This paper discusses how this partnership can be strengthened to ensure budgeting supports both fiscal sustainability and the effective delivery of government priorities.

While traditionally focused on detailed control of individual spending items, budget offices are now expected to guide the overall shape of the budget while enabling better policy outcomes across government. At the same time, line ministries are taking on greater responsibility for allocating and reallocating resources, managing their budgets over the medium term, and being accountable for the results achieved with public funds.

Changing the relationship between budget offices and line ministries cannot be achieved solely through procedural reforms. It requires professional capability on both sides, shared understanding of policy and financial pressures, and consistent behaviours throughout the budget cycle. Experience from OECD countries highlights three pillars that are critical to making this transition effective:

• strengthened expertise within both the budget office and line ministries to plan, manage and reallocate resources
• effective interaction throughout the budget cycle, built on clear roles, structured processes and regular communication
• active participation of line ministries in the design and implementation of budgeting reforms, ensuring relevance and ownership.

Key recommendations

• Strengthen the finance functions in each line ministry
• Invest in skills and systems across government
• Enhance digital infrastructure and data use
• Foster a culture of trust and shared accountability
• Ensure co-ordination between the Centre of Government and the budget office
• Strengthen top-down budgeting and medium-term planning.