Westpac Group has launched an enquiry at the same time as Australian regulator ASIC and the Australian Bankers' Association are reviewing the mortgage market.
Brokers now have about half the Australian mortgage market, up from 30% five years ago.
David Bailey, of AFG, which represents brokers, told media it would be possible to be cynical about the timing of the view.
"There is a lot of head scratching going on amongst brokers," Bailey was quoted as saying. "There is a good alignment of broker payments to outcomes. House buyers are happy or they would not keep coming back. I'm not sure what else Westpac needs."
As well as looking at commission, the bank will consider complaints procedures, support for "whistle-blowers", ways of removing offenders from the industry, supporting ASIC and strengthening customer commitment.
A letter to brokers said it would be in touch about the review without saying when.
Brokers have asked for more information on the review criteria, who will be asked for evidence, whether the findings will be published and how they will be used.
But a Westpac spokesman said there were no plans for a similar review in New Zealand.
