Jim Chalmers to confirm first back-to-back federal budget surpluses in more than 15 years

Treasurer cites lower government spending as the key driver behind the $15.8bn surplus, which is $6bn better than May's forecast

• Get our breaking news email, free app or daily news podcast

Jim Chalmers will on Monday reveal a $15.8bn budget surplus in an economic update, more than $6bn higher than predicted at May's federal budget.

The treasurer says the better-than-forecast budget position has come entirely" from lower government spending, a detail the treasurer highlights as Labor comes under scrutiny from the opposition and the Reserve Bank over concerns that public expenditure is helping to drive inflation.

Sign up for Guardian Australia's breaking news email