Consumer group Choice is advertising to find a buyer to save BankWest from being acquired by the Commonwealth Bank of Australia (CBA) in a takeover it said would be “disastrous for both customers and competition”.

The group has placed a series of ads in a national newspaper calling for a responsible buyer that is not one of the ‘big four’ banks to pick up the Perth-based regional bank.

Choice spokesman Christopher Zinn said if the deal was “allowed to proceed by the [Australian Competition and Consumer Commission] and the Treasurer, consumers will face a very cosy oligopoly”.

“Any takeover will increase the market dominance of the ‘big four’ banks in lending and deposits.”

Zinn said BankWest’s plans for more than 100 new BankWest branches across the Eastern seaboard have already been scrapped by the CBA.

“We can’t afford to lose this dynamic, aggressive and effective competitor. BankWest’s innovative products and services have been critical in challenging the ‘big four’,” Zinn said.