Westpac Bank is looking to close a number of branches around the country.
The bank confirmed a "consultation" was underway with staff and First Union said up to 19 branches could be closed.
A statement from the bank said the rise in online transactions was behind the proposal.
"Currently more than 85 per cent of service transactions with us take place outside of a branch."
The bank wouldn't confirm the number of branches that could be closing, saying "a number of branches" were included in the proposal.