More than 450 bank branches in regional areas are "at risk" of closing due to their smaller population size, despite having fewer accessible locations for physical banking services, new analysis suggests. 

The analysis by location advisory company AreaSearch examined 3,197 existing branches run by 27 banks around Australia, finding the average bank services 8,200 people per branch nationwide, while those in the regions serve an average of 4,600 customers.

But regional areas with a population greater than 10,000 people are more likely to be without a "convenient banking service", and in some cases are more than 100 kilometres away from their closest alternative.

In addition to the big four banks of the Commonwealth Bank, Westpac, NAB and ANZ, the data also collated branches operated by smaller financial institutions, including Suncorp, St George, Heritage Bank and Bank Australia.

AreaSearch calculated the number of branches based on what was publicly available on each bank's website, and excluded services like Bank@Post.

The analysis follows the bosses of Australia's big four banks telling a September Senate inquiry how they determined which branches would close, in response to more than 1,600 regional branches closing in six years.

The bank bosses said the decision to close a branch was based on a combination of declining foot traffic, a reduction in in-store transactions, and increased demand for online banking services — although NAB was forced to admit it closed a branch despite a rise in transactions.

Given fewer people live in regional towns, AreaSearch's analysis said smaller towns were at risk of being left without a bank due to their low populations, which would disadvantage communities and their typically "older, more vulnerable" residents.

"This highlights the stark contrast across the country, with 454 regional branches identified in our analysis that appear vulnerable and service an effective population under 2,500 people per branch,"  AreaSearch analyst Ronan O'Carroll said.

He said the average distance people would have to travel to access a physical branch would double if the branches were to close — but noted the distances were often greater due to the vastness of regional Australia.

"On our numbers at present, there is an average distance of 9.4km between each residential address and their nearest bank in regional Australia," Mr O'Carroll said.

"This puts older, more vulnerable cohorts in particular at risk, given they could be forced to travel considerable distances to access their finances physically, while impacts on cash-reliant businesses would obviously also be significant."

Mr O'Carroll however noted that the doubling of distance was a "worst-case scenario".

He also said there were a large number of "cash-free" towns, or those that had no banking options within a 5km radius, with 11 towns having a population greater than 10,000 people.

"This highlights the gravity of the situation in regional areas, suggesting many local branches are likely not viable from a business perspective," he said.

'There's no easy solution'

Although hundreds of regional banks are considered "vulnerable", AreaSearch founder Chris Freeman said there was no guarantee a smaller population was the deciding factor in whether branches would close.