Australians could have some of the cheapest power bills in the world if the nation's energy resources are better used, a big bank boss says.

NAB chief executive Andrew Irvine labelled the nation's energy mix "sad" and said achieving net-zero emissions by 2050 was possible if renewables were harnessed.

"Australia should be an energy superpower," Mr Irvine told a parliamentary inquiry into the big four banks on Wednesday.

"We are blessed with incredible amounts of sunshine, wind resources, with some hydro capacity, and one of the world's largest reservoirs of natural gas.

"The fact that we are in a situation where we have a possible issue with a supply and demand imbalance on energy is sad and shouldn't have happened."

He said there was too much political debate around net zero and ener

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