The CML said it was clear that the Financial Conduct Authority's focus and its ways of working are likely to be different from those of the Financial Services Authority.
The FCA consultation published today suggests there will be a greater element of judgment involved in relation to individual firms' business models, practices and product offerings.
The new FCA approach to product intervention will be pro-active and pre-emptive and firmly aimed at preventing consumer problems.
And the CML warned this potentially creates a "very different operating environment for firms".
As the FCA noted it will be important for the new regulator "to communicate more effectively with firms that want to do the right thing, and we must be clearer about our expectations".
The CML welcomed the FCA's intention to "engage more with firms, trade associations, the practitioner panels and other relevant stakeholders when we start pieces of thematic work on issues and products".
And the trade body said it was also important to ensure that heads of supervision with responsibilities for specific sectors will "engage with groups of firms and trade associations, as appropriate, to gain a more in-depth understanding of specific sectors, along with building an open and transparent relationship".
Paul Smee, CML director general, said: "The FCA will have an armoury of new consumer powers at its disposal, some of which - like product intervention - are untried and untested.
"Firms will be looking for as much information and help as possible from the FCA, to ensure that they do not inadvertently fall foul of the regulator's expectations.
"The challenge, for firms and the FCA alike, will be to meet the regulator's aspiration of allowing businesses room to try new ideas, while at the same time minimising uncertainty for them about whether those ideas will successfully leap the regulatory hurdles.
"We will engage with both the FCA and the PRA, and hope for a high level of dialogue and communication with both regulators."
The Financial Services Authority published Journey to the FCA this morning - a paper that gives more detail about how its successor, the Financial Conduct Authority, will operate.
This follows yesterday's document from the Bank of England and the FSA on the Prudential Regulatory Authority's approach which said it wanted to set clear standards for firms, but that its "approach will be very clearly based on judgement rather than narrowly rules-based."
