The Reagan administration is continuing to play political hardball with Sen. Charles H. Percy (R-Ill.), the chairman of the Senate Foreign Relations Committee, for leading the fight against the nomination of Ernest Lefever as assistant secretary of state for human rights.

White House political adviser Lyn Nofziger told reporters in Chicago Monday that the nomination of DAN K. Webb, Percy's choice to become U.S. attorney in Chicago, still is being held up and that Percy should "understand that it is a two-way street." There were reports during the debate on Lefever's nomination that the White House was blocking Webb's candidacy to put pressure on Percy.

The Chicago Tribune reported that Nofziger also said he felt the appointment of a U.S. attorney "should receive the same kind of consideration as the appointment of an assistant secretary of state." Lefever withdrew from the nomination after Percy and other members of the Foreign Relations Committee voted against reporting his name favorably to the full Senate.

"I think the Senate ought generally to give the president what he wants," Nofziger was reported as saying. "There will be times when they [senators] want someone nominated. . . . I hope Sen. Percy understands it is a two-way street."

One administration source said yesterday that the Webb nomination probably will be approved eventually after the political loyalty point is made.

A spokesman for Percy said that the senator continues to back Webb and "expects he will be nominated." Webb's nomination is different from Lefever's, the spokesman said, because "Mr. Webb is very well qualified for the job." It was clear from the Lefever hearings that Percy did not feel the same way about the human rights nominee.

Webb, in the meantime, says he is in limbo. "I let people know I would accept the nomination as U.S. attorney. And now I can't take any new clients," he said.

He served as an assistant U.S. attorney for six years in Chicago and more recently headed the Illinois state department of law enforcement under republican Gov. James Thompson -- himself a former U.S.. attorney in Chicago.

Webb said he found it ironic" that his nomination was being blocked in the Reagan White House because he had supported the president in the campaign, serving on a lawyers' committee for Reagan and making a contribution to the candidate. "I think it's a little bit unfair. I find myself in the position of being punished. And it's not like I'm a guy on the other side of the fence. I was an active Reagan supporter."

In his remarks to reporters in Chicago, Nofziger said that another candidate for the U.S. attorney's job is "very much under consideration." James Donnelly is being pushed for the position by state Sen. Donald Totten, who headed Reagan's campaign in the Midwest.