Former Internal Revenue Service official Lois Lerner, a central figure in the IRS scandal, will appear before Congress on Wednesday after refusing to testify last year on the matter, Rep. Darrell Issa, R-Calif., claimed Sunday -- though Lerner's attorney and Issa may still be at odds over the timing.

Issa, chairman of the House Committee on Oversight and Government Reform, told “Fox News Sunday” that Lerner’s lawyers have indicated she will testify before his committee, after saying last week that she would not.

“It’s going to be a good, fact-finding hearing,” he said.

Issa said he didn’t know why Lerner’s lawyers changed their mind, but suggested Lerner testifying was “in her best interest,” considering the recent evidence the committee had gathered.

Later in the day, Lerner attorney William W. Taylor disputed Issa’s claim, saying his client would not testify.

“As of now, she intends to continue to assert her Fifth Amendment rights,” Taylor told Politico. “I do not know why Issa said what he said.”

Taylor’s statement was followed by a release from the oversight committee that stated Taylor had confirmed in writing that his client is willing to testify but wants to delay the hearing by one week.

“We have informed Mr. Taylor that Ms. Lerner may make her request for a delay on Wednesday when she appears for the hearing,” said committee spokesman Frederick Hill.

Issa and Lerner’s attorneys also have argued about whether she is protected under the Fifth Amendment from having to testify.

In May 2013, Lerner invoked the amendment right during her first-and-only appearance before the House committee, but only after she said during an opening statement that she broke no laws.

Lerner resigned last year from her post as the agency’s director of tax-exempt organizations.

The House committee continues to investigate the IRS in its 2012 targeting of Tea Party groups and other politically conservative organizations trying to get tax-exempt status.

Congressional investigators are trying to determine who exactly gave the orders for IRS agents to target the groups.

Issa said Sunday that Lerner was “in a powerful position and could have been acting alone.” Congressional documents also suggest that she was under political pressure to orchestrate the targeting.

However, safeguards against such situations should have been in place and Congress should work to put in “more checks and balances,” he also said.

Last week, Lerner attorney William Taylor said his client would testify on Capitol Hill only if compelled by a federal court or if given immunity for the testimony.

Taylor stated his position in a letter to Issa. He was responding to a letter Tuesday from Issa saying, in part, that Lerner’s testimony remains “critical to the committee’s investigation.”