WASHINGTON  The Republican who will lead the chief investigative committee in the House is planning to vastly expand scrutiny of the Obama administration by seeking new subpoena powers for dozens of federal agency watchdogs in hopes of using their investigations and his own in an aggressive push to cut spending and shrink the government.

The Republican, Representative Darrell Issa of California, who will take over as chairman of the House Oversight and Government Reform Committee, has said the government needs “to go on a diet” to help erase the annual budget deficit of $1.4 trillion. His goal as chairman, he said in a recent speech, is to “focus on places where money can be saved, where we can literally close agencies or subagencies or programs.”

It is a far broader policy mandate than was embraced by predecessors in both parties, who viewed their role as chief Congressional inquisitor of the executive administration. “What my committee has to do is, it has to stretch what it has done in the past,” Mr. Issa said.

His agenda may surprise some Congressional Democrats and White House officials who are bracing for Mr. Issa to paper Washington with investigative subpoenas in a broader crusade to bring down President Obama.