By Poppy Johnston in Canberra

Any windfall in the mid-year federal budget update is expected to fall well short of revenue upgrades of the past few years.

Treasurer Jim Chalmers has played down the size of revenue write up, citing a slowdown in the jobs market, weaker corporate tax revenue and structural challenges in the Chinese economy dragging down iron ore prices.

“There’s still a fair bit of data to land before MYEFO, including national accounts and tax collections, but Treasury’s latest estimate is that any upgrade will be a sliver of what we saw in those first four budget updates,” Dr Chalmers told parliament on Wednesday.

The average revenue upgrade in the past four budget updates has been $80 billion.

AMP chief economist Shane Oliver agreed “the years of the rivers-of-gold tax revenue flying into Canberra were probably behind us”.

“I don’t think it’s going to be anywhere near the scale of upgrading seen in recent years because the jobs market hasn’t been significantly better than expected,” he told AAP.

Similarly, the iron ore price was a little ahead of typically conservative Treasury forecasts but not dramatically higher as it had been in the past.

Dr Oliver said corporate profits outside of mining were generally “quite soft”.

“So any upside surprise we do see, it’s going to be far more modest,” he said.

The mid-year economic and fiscal outlook will be released in December.

Shadow Treasurer Angus Taylor urged Dr Chalmers to use the opportunity to restore budget discipline and tame inflation.

He promised a “back to basics economic agenda” if the coalition won the upcoming federal election.

“Fighting high prices and interest rates first, winding back regulatory roadblocks, boosting productivity and delivering lower, simpler and fairer taxes,” Mr Taylor said in parliament on Wednesday.

While the strength of the labour market and commodity prices have helped the government repair the budget position and deliver back-to-back surpluses, Dr Chalmers said the turnaround “hasn’t been accidental or incidental”.

“We’ve found almost $80 billion in savings, banked the majority of revenue upgrades and saved tens of billions of dollars in interest on debt as a result.”

Treasury’s economic forecasts are expected to look similar to those in the May budget.

Rich Insight economist Chris Richardson said little change to inflation forecasts could be a clue to the fate of power bill relief.

“Sticking to their guns on inflation forecasts is certainly consistent with the thought that Mr And Mrs Suburbs get another year on their electricity rebates,” he told AAP.

In the May budget, Treasury forecast headline inflation at 2.75 per cent in the year to June 2026.

The Reserve Bank of Australia has the headline rate jumping back to 3.1 per cent at that time, assuming the electricity rebates end.