Two state lawmakers are calling for officials to shine a spotlight on a pending hospital merger that would create the state’s second-largest health care system.

Reps. Frank Moran and Russell Holmes each wrote letters to Attorney General Maura Healey and Health Policy Commission executive director David Seltz, both voicing concerns “that there has been little public debate or scrutiny” around the proposed merger led by Beth Israel Deaconess Medical Center and Lahey Health.

The 13-hospital merger received a green light from the state’s Public Health Council and is under review by both the Health Policy Commission and Healey’s office.

Officials from Beth Israel and Lahey have said the deal will lower costs and allow better coordinated care, while opponents caution that the major new system could destabilize the health care market, threatening patients’ access to care.

“I understand that [Department of Public Health] conducted a few public hearings and HPC is conducting a cost impact review,” Holmes and Moran wrote in their separate letters. “However to the general public, most of this is happening behind the scenes. We have not seen the type of mainstream public discussion that a merger of this magnitude deserves.”

Both ask for the review process “to be as transparent as possible,” with opportunities for their constituents to participate in discussion.

An initial Health Policy Commission review found the new Beth Israel/Lahey system would have the “second largest inpatient, outpatient and primary care market shares in the commonwealth,” behind Partners HealthCare. More than half of inpatient care provided across Massachusetts would come from those two systems, according to the commission.