Tory Frank Klees says a transcript of an emergency call shows Ornge replied to a request for an air ambulance Wednesday morning by saying it had no resources.
The victim was transported by land ambulance from the crash scene in Whitchurch-Stouffville and later died in hospital.
An Ornge spokesman confirms the service received a call this morning to attend the scene of the collision.
James MacDonald says Ornge has two helicopters at its Toronto base but one crew was on another call at the time and the second had a later start time after working late Tuesday.
He says Ornge extends its sincere condolences to the family of the victim and its thoughts are with them.
Police say the driver of a cube van died in hospital after a collision with a Mack truck at about 6:30 a.m. The truck's driver had minor injuries.
In the legislature, Klees and New Democrat France Gelinas questioned how Ornge could find itself unable to respond to an emergency at a time when it is under such a spotlight.
"For months, we've been warning the minister about the staffing policies at Ornge that leave bases understaffed and incapable of responding to emergency calls," said Klees.
Reading from the transcript of the call, Klees asked Health Minister Deb Matthews to explain why staffing at the ambulance service is not being properly addressed.
"The person in question had to be transferred by land ambulance. He died," said Klees. "I ask the minister, if ensuring proper staffing levels was not a priority for her leadership team, what was?"
Matthews said she would look into the details of what happened, adding that staffing is a "very high priority for the new leadership at Ornge."
The ambulance service is under a criminal investigation and its previous executives and board of directors have been replaced with new leaders.
"They are working very hard to get the right staffing in place so that they can provide the best possible care for the people of this province," said Matthews.
MacDonald said in an emailed statement that "an aircraft was not available from the Island Airport because one crew was actively engaged in another call."
"The second crew had a later start (1.5 hours) as they went beyond their 12-hour shift the previous day due to a patient transport."
"In order to comply with Transport Canada regulations, a later start time was required," he said.
NDP Leader Andrea Horwath said outside the legislature that people need to know they can rely on air ambulances.
"The health minister needs to take some responsibility for an air ambulance service that’s been under such heavy scrutiny and yet continues to not deliver," Horwath said.