The corporate regulator has banned Commonwealth Bank's financial planning arm from charging ongoing service fees until further notice after a report found the business had inadequate systems in place to protect its customers from being ripped off.

In an embarrassing rebuke that landed just hours before the final report of the banking royal commission was handed down on Monday afternoon, the Australian Securities and Investments Commission also took Commonwealth Financial Planning to task for failing to satisfactorily complete its homework as part of an enforceable undertaking. The fee freeze applies to all of the business' clients and also prohibits CBA from entering into any new arrangements. CBA said the ban would lead to a one-off pre-tax profit hit of $40 million.