The Reserve Bank has warned that self-managed super funds' growing investments in real estate have opened up another avenue for property speculation, which could affect the financial system's stability.

In its latest health check on the financial system, the central bank on Wednesday said some households running their own retirement funds were taking on more financial risk.

It singled out the increasingly popular strategy of borrowing to invest in houses within a self-managed super fund, which it said ''represents a vehicle for potentially speculative demand for property that did not exist in the past''.

Amid rapid growth in the DIY super sector, the Reserve noted the strategy had been ''heavily promoted'' and it was assessing the effects on the financial stability.