The Food and Drug Administration is allowing some high-risk devices like artificial hips to be sold without strenuous testing, despite promises that it would address regulatory issues affecting them, a federal watchdog group plans to testify on Wednesday.

The group, the Government Accountability Office, found that the F.D.A. has taken some recent steps to determine if certain high-risk medical devices should undergo more testing before being sold. But in the meantime, it is continuing to approve dozens of such devices annually with scant review, exposing patients to risks.

An official with the office is expected to give the testimony on Wednesday at a hearing before the Senate Special Committee on Aging. The office will also present its preliminary findings of what it concluded were shortcomings in how the F.D.A. oversees recalls of troubled devices.

A spokeswoman for the F.D.A., Karen Riley, said that officials there had not seen the G.A.O. testimony and so could not respond directly to it. She added that F.D.A officials planned to testify at the hearing. The panel is also expected to hear from patient advocates and industry representatives.