Bankwest is closing 29 branches along Australia's east coast and cutting 200 jobs, saying customers are increasingly using mobile banking.
Bankwest, which is owned by Commonwealth Bank, says the branches will close over a three-week period from August 17, reducing its east coast footprint to 14 branches.
Managing director Rowan Munchenberg blamed rapid changes in the digital space and said Bankwest could not match the physical footprint of the bigger banks.
"We're seeing a consistent trend of customers choosing mobile banking over in-branch options for their transaction needs, with an 88 per cent rise in app logins over the past three years," he said on Wednesday in a statement.
Mr Munchenberg said the bank's operations are being overhauled to "respond more rapidly" to changing customer needs.
"But we know we can't match the major banks' nationwide footprint and also deliver world class digital services, so we will prioritise digital channels and broker relationships," he said.
The Finance Sector Union has lashed out at the branch closures, saying the move is designed to maintain CBA's profits at the expense of customers and jobs.
Finance Sector Union national secretary Julia Angrisano said the decision - which closes 68 per cent of east coast branches - had come as a shock to the bank's employees.
"For an entire branch network to almost disappear overnight will have lasting impacts on Bankwest employees, their customers and the communities in which they belong," Mr Angrisano said.
A Bankswest spokesman said the company will endeavour to find new roles for the 200 staff within CBA's operations.
More than half the branch closures are in NSW, with the rest in Victoria and Queensland.
Bankwest has 82 branches and three business centres in Western Australia, the spokesman said.
