Rate rises may be limited: IMF

As consumers and businesses worry about an interest rate rise from the Reserve Bank before long, a new analysis suggests any increases are likely to be limited.

The International Monetary Fund says worldwide interest rates are expected to increase in the medium term with global economic conditions normalising, reversing the decline into negative territory due to the 2008-2009 global financial crisis.

But in the analytical chapters of its forthcoming world economic outlook, the IMF does not believe real, or inflation adjusted, interest rates will return to high levels.

"The increase from current levels is expected to be modest, because the factors that have mostly contributed to low real rates in the past recent years are unlikely to reverse substantially," the report released in Washington on Thursday said.

It says the "scars" from the GFC have resulted in a sharp and persistent decline in investment in advanced economies, while there will be only a modest impact from lower savings in emerging market economies as a result of slower economic growth.

There has also been an investment shift to safer interest-rate yielding bonds away from riskier equities, which has kept rates low.

Using data from a number of countries, including Australia, it found that 10-year real interest rates declined from an average of 5.5 per cent in the 1980s, to 3.5 per cent in the 1990s, to two per cent between 2001 and 2008 and to slightly negative territory of 2012.

While continued low real rates will help borrowers to lower debt ratios, they also raise new policy challenges.

"The envisioned low real rate environment ... may re-emerge as a constraint to monetary policy should risks of very low growth in advanced economies materialise," it said.