U.S. Treasury Secretary Jacob J. Lew urged Congress and financial companies to step up their fight against cyber threats, saying malicious acts pose a risk to national security and financial stability.

"Our laws do not do enough to foster information sharing and defend the public from digital threats," Lew said today at the Delivering Alpha conference in New York. "We need legislation with clear rules to encourage collaboration and provide important liability protection."

Financial firms such as hedge funds and asset managers "should and could be doing more," Lew said.

"Disclosing security breaches is often perceived as something that could harm a firm's reputation," he said. "This has made many businesses reluctant to reveal information about cyber incidents. But this reluctance has to be put aside."

Lew said he discussed cyber threats during meetings with Chinese officials in Beijing last week and told them that "government-sponsored, cyber-enabled theft of intellectual property for commercial gain is illegal and unacceptable."

The conference is held by CNBC and Institutional Investor.