Watch out for another financial crisis if we slow the push for financial reforms, says a key architect of the Dodd-Frank Act.

Since the Lehman Brothers bankruptcy brought the financial system to its knees five years ago, legislators and regulators have been pushing reforms to rein in the financial sector and prevent another crisis.

"The financial sector is still lobbying, litigating and seeking to legislate to block them [regulations]. If we don't keep pushing, we could find ourselves wondering why we're in another crisis five years from now," writes Michael Barr, former assistant secretary of the Treasury, in blog for CNBC.

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Despite a plethora of new regulations, much work remains to be done, says Barr, a law professor at the University of Michigan Law School and senior fellow at the Brookings Institution and the Center for American Progress.

The many incomplete reforms include capital rules, "bail-in" debt and limits on counterparty credit exposures.

"Structural reforms such as the Volcker Rule and limiting large firms to no more than 10 percent of the liabilities of the financial system are not yet in place" he points out.

"Short-term wholesale funding, while reduced, still poses the risk of runs throughout the financial sector, and money market funds are still susceptible to the same kind of runs that led to their 2008 bailout."

Although the Lehman Brothers collapse has become the symbolic spark of the crisis, the roots of the cause were deeper and broader, Barr notes. They can be traced to years of Wall Street excesses and regulatory complacency.

Shadow banking permitted highly leveraged, opaque transactions, and large interconnected firms relied on short-term funding from repo transactions. In addition, financial firms evaded oversight through legal loopholes, regulatory gaps and off-balance sheet activities.

"There is a serious risk that a collective amnesia about the causes and consequence of the financial crisis will further weaken the resolve for reforms," he warns.

While critics say regulators have been slow to implement new rules, the pace of reforms has actually been frenetic, according to The Wall Street Journal. New rules on liquidity derivatives, accounting standards and executive pay are now in place.

The disquieting question is why the global financial system is not working well despite new rules, writes The Journal's Simon Nixon, noting that financial institutions are reducing liquidity by scaling back their cross-border exposures.

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