Members of the Treasury Select Committee have published a special report into the government's "defective" banking reforms, according to reports.
MPs fear the government is trying to rush through laws that will leave the "financial system over-complicated and outdated", the Telegraph said.
The FT reported the 37-page report would highlight the flaws of the proposed bill in the hope of sparking changes when it goes before the House of Lords next week.
Committee chairman Andrew Tyrie said: "The Financial Services Bill is the most important overhaul of financial regulation ever undertaking in this country. Better to take a little more time, and get it right, than rush it."
It said the influential panel of MPs do not have issue with the main purpose of the bill - which will split the Financial Services Authority (FSA) in two, give prudential regulation of banks and insurers back to the Bank of England and set up a new Financial Conduct Authority.
But the committee does want the bodies to be more accountable to parliament and for the court of the BoE to be replace with a "stronger oversight" body with the power to review performance and policy decisions, the FT said.
It also wants the Prudential Regulation Authority to include enhanced competition as one of its objectives, the report added.
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