Ontario's opposition parties united on Thursday to demand the Liberal government take further steps to probe the province's scandal-plagued air ambulance service.

In a rare step, the Conservatives and NDP held a joint press conference to request the creation of an all-party committee designed to "get to the bottom of what has become known as the Ornge scandal."

Conservative MPP Frank Klees said the integrity and ability of the air ambulance service has been thrown into question and has left the public concerned for their safety and wondering who can be trusted to restore the service.

"This issue has dominated not only the legislature since it reconvened two weeks ago, but has become a topic of much discussion among the public right across the province. And rightfully so," Klees said on Thursday.

Ornge has been the subject of a criminal probe over financial irregularities and an investigation by the Ministry of Health into 13 incidents related to air ambulance transports, three of which involved the deaths of patients.

The board of directors was removed after questions were raised about how the organization spent $150 million in annual funding it received from the province.

CTV News has also learned that Ornge was forced to ground their ambulance helicopters for nearly 47,000 at the start of the year due to a shortage of pilots and medics.

The opposition parties have demanded Health Minister Deb Matthews resign from her post. Matthews insists she is not stepping down and continues to lead an investigation into irregularities

NDP Health Critic France Gelinas also demanded the creation of an all-party committee that would investigate the issues of executive compensation, oversight and public accountability by holding public hearings and offering protection to whistleblowers.

"New details about how Ornge executives diverted public health care dollars away from front line care are surfacing every day as more whistleblowers come forward," she said.

"It is our duty as elected representatives to act on behalf of the public to ensure the truth is revealed and that is why a select committee is needed urgently."

Auditor general Jim McCarter is compiling a report on Ornge which is expected to be released later this month.