Nearly 3 million Australians are at risk of credit default – which could see their all-important credit score fall – in the next 12 months, according to new figures.

A default occurs when, for example, you haven't paid a mobile phone bill of $150 that is 60 days overdue. A low score could stop you from getting a credit card or a mortgage.

The average credit score this year is 757, down 14 points on last year's figure but still considered "very good", according to the largest credit bureau Veda. Scores can range from zero to 1200.

The highest average score was in NSW's Sutherland region, while the lowest was in Queensland's Logan-Beaudesert region, south of Brisbane.