Investigators from the Department of Emergency Services wrote to the minister about the lack of response times from call-takers.
One letter noted that the pressure on triple 0 was almost identical to that of a thunderstorm asthma incident in 2016.
An investigation by the inspector general of emergency management revealed that the response times had not improved for another three months.
An inquest is currently being conducted into the death of Nick Panagiotopoulos, who died after he was unable to get through to a triple 0 operator for over 16 minutes.
IGEM is responsible for monitoring the operations of the emergency services authority in Victoria, which is known as Triple Zero Victoria.
During the investigation, Christopher Mercovich, an IGEM senior officer, said that during the peak of the call-handling situation in October 2021, ESTA was able to answer 47.4 percent of the calls within five seconds.
However, by January 2022, the agency only managed to answer 39 percent of the calls.
The main issue with the call-handling situation was the lack of call-takers.
According to Mercovich, the agency was reluctant to increase its staffing levels in 2020 due to the belief that it had already spent too much.
He said this belief prevented the agency from requesting additional funding.
Three letters were then sent to the emergency services minister in October and November 2021, expressing concerns about the issue.
However, IGEM did not take the necessary steps to address the situation. He said the agency was not the regulator of the ESTA and could not fix the issues.