Cabinet minister Steven Ciobo says a banking royal commission will only benefit lawyers, after three coalition MPs threatened to support the renewed push.

Warren Entsch, George Christensen and Ann Sudmalis have indicated they are considering crossing the floor to help launch the big bank inquiry.

They have been emboldened by former deputy prime minister Barnaby Joyce's exit from parliament, as the number of votes required have slimmed.

Queenslander Warren Entsch told 7.30 "all hell will break loose" if his demands aren't met by the end of the month.

Mr Entsch said Treasurer Scott Morrison had promised him a number of specific allegations of bad bank behaviour would be investigated but has not followed through.

Mr Christensen and Ms Sudmalis are believed to be frustrated by the lack of action and are considering their options.

But Mr Ciobo has implored his colleagues to reconsider.

"The royal commission would do basically next to nothing except see millions and millions of dollars go into lawyers pockets rather than actually bringing about the cultural change that's required," Mr Ciobo told ABC radio today.

His concerns follow those of acting prime minister Julie Bishop, who also told 7.30, "We want to work with those MPs and others who have constituents who are concerned about the relationship they had with their bank."

"A banking royal commission will not provide them with redress.

"It would only make recommendations and that could be years away and that's why we're trying to take action now.

"I'm sure my fellow members of Parliament understand that."