Pasqua Hospital's ER will close its doors between 7:30 p.m. and 8 a.m. each day starting next week for at least the next three months.
People who need emergency services in Regina between those times will have to go the General Hospital.
The Regina Qu'appelle Health Region says despite efforts to recruit doctors, staffing levels are still one-third below what is needed to fully staff both emergency departments.
An official with the health region says it is working with the province, doctors, senior management and staff to create short- and long-term solutions to this problem.
It also says a task force has been formed to remove barriers to emergency room physician recruitment and retention, and to look at quality of working life issues.
"In mid-October, the region advised the public that it was facing a shortage of appropriately-credentialed emergency physicians," said Dr. David McCutcheon, vice-president, physician and integrated health services for the health region.
"The region has employed aggressive recruitment efforts; however, the situation has not improved in the past month, with staffing levels still approximately one-third below what is needed to fully staff both emergency departments. (The region's) emergency department physicians have been working extra shifts to address the shortfall.
"Despite the best efforts of our management, physicians and staff, this reduction in services has become necessary in order to ensure that we can continue to provide safe, quality care to our patients."
Patients in care at Pasqua when the ER closes nightly will be discharged, admitted or transferred to the General hospital ER department, and ambulances will be directed to the General.
Health officials are urging people with less-urgent needs to go to their doctors, or walk-in clinics or the Meadow Primary health care centre.
"We regret the inconvenience to patients, and are making every effort possible to limit the duration of this service disruption," McCutcheon said.