Hackbarth appeared before the House Energy and Commerce health subcommittee, which kicked off its legislative session with a hearing on Medicare payments to doctors.
House GOP committee chairmen have promised to put an SGR reform bill on the floor by August recess.
In exchanges with members, Hackbarth spoke about the advantages of new payment models, the threats to U.S. primary care, and the dangers of keeping the SGR in place.
"We have all heard about the problems for access to care for Medicare beneficiaries in particular markets," he said. "MedPAC's fear is that those problems could spread rapidly if SGR is continued."
The formula subjects doctors' Medicare reimbursements to annual cuts, which Congress consistently delays using a temporary "doc fix."
Physician groups strongly support repeal of the formula, saying it creates uncertainty in the healthcare system and discourages doctors from seeing Medicare patients.