Under the changes, the pensionable base for men with the full 40 years of service would increase from 57.25% to 63.5% by 1 January 2025. Meanwhile, the latter figure is already in place for women.

The Fiscal Council said that the government should provide long-term projections before the end of the public debate in early September.

The government should provide projections at least until 2040, as the measures would take full effect in 2025, the year that marks the start of a period expected to see an additional increase in the number of pensioners.

In the short-term and medium-term, increases planned in social transfers could undermine long-term sustainability of public finance without measures to offset these effects.

If passed in their current form, the changes could undermine Slovenia's medium-term fiscal goal and could require additional fiscal efforts to honour the fiscal rule Slovenia has enshrined in the Constitution, the Fiscal Council said.

Although the changes include measures to promote work past the pensionable age, the effects of these measures are harder to asses, the council said.