Australian-listed resources companies are spearheading an inflation-fuelled investment boom, as they dial back shareholder payouts and divert a record amount of cash into buying and upgrading assets.

Companies in the S&P/ASX 200 spent 55 per cent of their free cash flow on capital expenditure in July-December, Goldman Sachs says. That marked a significant jump from the 41 per cent spent a year earlier, and means spending, in nominal terms, has surpassed the peak of the commodities boom in 2012.