A glitch in Victoria's emergency computer-aided dispatch system on Friday night meant that dispatchers had to use a manual backup system for up to three hours, in what was the third such fault in the system within two months.
Health Minister David Davis conceded that the glitch was "not ideal", with Emergency Services Commissioner Michael Hallowes to investigate.
He said the best way to deal with the matter is to wait until the independent review.
"We need to understand precisely what has occurred here, and that's why I welcome the intervention of the Emergency Services commissioner," Davis told reporters on Sunday.
"He will get to the bottom of any impacts that have occurred."
However, the ambulance union said an interim measure is needed before the review is handed down to ensure the system doesn't fail again.
"While we're waiting for an outcome, an investigation, I keep my fingers crossed that it doesn't go down again," Ambulance Employees Association Victorian secretary Steve McGhie told AAP.
"We can't afford to have the system down the way it was across the state, because there's no doubt it puts lives at risk by delaying responses of ambulances to people that need them.
"Thank God we didn't have some major thing going on in the state of Victoria where we needed multiple ambulances to respond to, because we didn't have the communication system that could cope with it."
Cases are supposed to be dispatched within 90 seconds, but paramedics were reporting delays of up to 45 minutes when the system was down, McGhie said.
In one case at Melton, it took 45 minutes before an ambulance responded to a one-year-old child having seizures.
"When you resort to the manual system, it slows everything up and it takes longer to dispatch an ambulance," McGhie said.