Shocking accusations that a nurse murdered eight elderly patients in nursing homes in southwestern Ontario are prompting questions about the province's role in regulating nurses and monitoring long-term care homes.

Elizabeth Tracy Mae Wettlaufer, 49, was charged with eight counts of first-degree murder on Tuesday. She is accused of killing seven patients at the Caressant Care Nursing Home in Woodstock and one at the Meadow Park Nursing Home in London.

The NDP member of the provincial legislature for London-Fanshawe, Teresa Armstrong, brought up the charges in question period on Tuesday.

"There is a genuine question that people are asking this morning: How do murders go undetected for nearly 10 years inside any long-term care home in Ontario?" Armstrong asked.

Premier Kathleen Wynne and Attorney General Yasir Naqvi declined to answer Armstrong directly. "It would be highly inappropriate for any one of us to comment extensively on the ongoing police investigation," said Naqvi.

Nursing homes and the nursing profession are highly regulated in Ontario. The Ministry of Health and Long-Term Care is responsible for monitoring nursing homes. The College of Nurses of Ontario oversees and regulates the 150,000 nursing professionals in the province.

'Rigorous' oversight of nursing homes: minister

Under provincial law, long-term care homes are required to notify the coroner of every death. An autopsy is not mandatory, but the coroner has the power to order one.

Nursing homes are only required to notify the Health Ministry of deaths deemed "unexpected."

Health Minister Eric Hoskins said the system for ensuring the security and safety of nursing-home residents is "very rigorous."

"We have very stringent mechanisms in place to provide a high level of oversight, including annual inspections of all our long-term care homes," Hoskins told reporters at the legislature on Monday.

It's up to the nursing homes to ensure all nursing staff have the appropriate certifications and qualifications, according to the Health Ministry. Employees must submit to a criminal record check and sign a declaration to disclose any subsequent criminal charges.

Hoskins declined to say whether he plans to review the system in light of the murder charges.

"I know you have a lot of questions, Ontarians have a lot of questions and those questions will be answered," Hoskins said. "However, we're asking for patience and understanding at this extremely difficult moment of time."

Wettlaufer resigned day after police probe began

The College of Nurses of Ontario handles complaints about nurse conduct, such as violations of privacy, mistreatment or sexual abuse. Its website shows the results of all disciplinary hearings against nurses, as well as criminal charges relevant to their practice.

Until Wettlaufer was charged, her publicly accessible file with the college showed no disciplinary proceedings against her during her 21-year career as a registered nurse. About an hour after the police news conference revealing the charges, her file was updated to show the murder charges.

Wettlaufer is shown in this still image taken from video provided by Citynews Toronto in Woodstock on Oct. 25, 2016. (Citynews Toronto/Canadian Press)

"The College of Nurses of Ontario confirms that she is currently under investigation by the college and is not entitled to practise," said a statement from the regulator.

"The college is also co-operating with the police investigation. All publicly available information on Wettlaufer is posted on the online register Find A Nurse."

The file shows she became a registered nurse in August 1995 and resigned last month on Sept. 30, one day after Woodstock police say they received information that eight people had been killed in area nursing homes.

Woodstock, Ont., woman has been charged with killing eight elderly people at the nursing homes where she worked as a registered nurse 2:39

Wettlaufer is charged with the murder of eight people aged 75 to 96. The deaths occurred between August 2007 and August 2014.

Her Linked In profile shows she began working at Caressant Care in Woodstock in June 2007, just two months before the first death, and stopped working in 2014.