TORONTO -- A review of Ontario government oversight of nursing homes will be launched "at some point" if one is needed in the wake of a nurse allegedly killing residents, Premier Kathleen Wynne said Wednesday, but the criminal investigation comes first.

Provincial NDP Leader Andrea Horwath pressed the government on if it would conduct a review to ensure Ontario's 78,000 long-term care residents are safe, following news that a nurse was charged with eight counts of first-degree murder in the deaths of nursing home residents in southwestern Ontario.

That's exactly the question the police are trying to answer, Wynne said.

"It's absolutely imperative that the police have the opportunity to do the work that they need to do to get to the bottom of the questions that are obviously being asked by everyone, especially by the families of the people who have died," Wynne said in question period.

"At some point if there is a need for an independent review or an inquiry we will absolutely undertake that, not because of political pressure from the NDP, but because we all need to have the answers."

Ontario's oversight processes for long-term care homes are strong, said Health Minister Eric Hoskins.

"We have among the best oversight mechanisms for critical incidents as well as for general annual inspections in the world," he said. "We will continue to improve upon that strong, robust system."

Every long-term care home is obligated to report deaths of residents to the coroner, but deaths are only investigated when someone has died as a result of violence, "misadventure," negligence, misconduct, malpractice, "by unfair means," from any illness not being treated by a medical professional, "suddenly and unexpectedly," or "from any cause other than disease."

Long-term care homes are also required to immediately report unexpected deaths to Ontario's Ministry of Health and Long-Term Care and complete a full report within 10 days. The ministry reviews every critical incident -- there were more than 12,900 reported in 2014 -- to see if an inspection is warranted.

The auditor general last year looked at the long-term care quality inspection program and while she commended the ministry for hiring additional inspectors, she said there was a backlog in critical incident inspections, which placed residents at risk.

For-profit long-term care homes are subject to the same rules and oversight mechanisms as government-funded ones. All homes undergo an annual inspection by the ministry.

In the case which has captured national attention, the alleged victims were administered a drug, police said. Hoskins said every long-term care home is required to have a medication management system in place, approved by both the director of nursing and the pharmacist that provides the drugs to the home. It is reviewed quarterly by the home.

The College of Nurses of Ontario has a medication practice standard, by which nurses must abide, including not administering medication unless a proper authorization has been received.

All long-term care homes must only hire nurses who have a certificate of registration from the college, and they must undergo a criminal reference check, which includes a vulnerable sector screen.