The federal crackdown on insider trading could result in big new cases in the coming months, according to a senior regulator.

The Securities and Exchange Commission has “sprawling” investigations underway in several regional offices, and those are expected to lead to enforcement actions over the next six to nine months, Sanjay Wadhwa, a top official in the agency’s New York office, said at a recent conference for securities lawyers.

The probes apparently would break new ground. They are in addition to other pending investigations that have grown out of such highly publicized cases as the one involving the Galleon Group hedge fund and its former head, Raj Rajaratnam, Wadhwa said.

“We have a lot more in the pipeline,” Wadhwa said, speaking at the event Friday organized by the Practising Law Institute.

The SEC, the FBI and federal prosecutors over the past few years have charged a long string of hedge fund traders, corporate lawyers, boardroom insiders and others with trading on or trafficking in confidential information. The cases, some of which involved webs of tipsters and investors, have put the sharpest and most sustained focus on insider trading since Ivan Boesky was sent to prison a generation ago.

In October, hedge fund billionaire Rajaratnam was given an 11-year prison sentence, a record for insider trading. Rajat Gupta, a former Goldman Sachs board member who once headed the McKinsey consulting firm, is fighting criminal charges. In the Washington area, a former chemist at the Food and Drug Administration is awaiting sentencing for allegedly trading on inside information about drug approvals.

Some of the cases have focused on “expert network” firms, which introduced investors to corporate employees who fashioned themselves as consultants but were accused of selling secrets about the companies where they worked.

Since August 2009, 66 people have been charged criminally and 57 have been convicted in the Southern District of New York.

Each case tends to spawn more, lawyer Jacob S. Frenkel said, because defendants are pressed to cooperate with the authorities and point fingers at others in return for potentially more lenient sentences.

The ongoing probes include trading by institutional investors such as hedge funds, mutual funds and private-equity funds, the SEC’s Wadhwa said after the conference. If investigators’ suspicions are ultimately borne out, they could lead to cases as sensational as the Galleon case, he said.

The FBI in recent years has amassed dramatic evidence using wiretaps, a tactic once associated with targets such as organized crime. Rajaratnam was convicted largely on his own voice, captured in one conversation after another.

With evidence like that, “the lesson of Rajaratnam is all the money in the world cannot necessarily buy an acquittal at trial,” Frenkel said.

But, in his remarks at the conference last week, Wadhwa noted that the SEC, which files civil and administrative charges, does not have the power to conduct wiretaps, and he cautioned that cases the agency is pursuing will not always include them.

Wadhwa said the SEC has long been successful using more traditional methods.

In a case filed in September, for example, the SEC alleged that one defendant paid another, and it said the two defendants met at a Manhattan restaurant called Blue Ribbon Sushi. To support its case, the agency said that on four days when one of the defendants made bank withdrawals of $5,000 or more, the two swiped their fare cards at the same subway station “at the exact same time.”