A Commonwealth Bank survey shows the Australian dollar is below its "sweet spot" for businesses.

While the Reserve Bank and many industry groups have been calling for a fall in the dollar to boost export competitiveness, a falling currency also dents the profits of import-reliant firms.

CBA commissioned a survey of 200 medium-sized businesses (with a turnover of at least $10-100 million per year) to find out where the best balance was between a lower dollar favoured by exporters and a higher dollar for importers.

The study found that a level of 90-94 US cents saw the least number of businesses say that they were uncompetitive.

It found that a dollar below 84 US cents would cause pain for a significant number of importers, such as retailers, as the price of their overseas purchases would rise, either cutting profit margins or forcing price increases that may reduce sales.

The survey showed an Australian dollar above 93 US cents was the point at which most exporters started to become uncompetitive against their foreign competitors.

That means the current level of the Australian dollar - trading at 87.6 US cents at 4:29pm (AEST) - is at a level that is giving most exporters significant relief, but is not yet low enough to seriously impact importers, although it is getting close.

The bank's currency strategists say their 2012 research showed the "sweet spot" was around 80 US cents, implying that Australian businesses have adapted well to living with a persistently high currency.

The study also found that most businesses did not expect the currency to affect their investment or employment plans, although this was based on expectations of a year-end exchange rate around 91 US cents.