Ambulance Victoria's recent quarterly performance figures show Warrnambool, Colac-Otway and Moyne Shire ambulances are reaching patients faster, with a higher percentage of patients being reached within 15 minutes of the triple-0 call.

The statistics refer to code-one incidents where patients require urgent paramedic and hospital care. These patients receive a "lights and sirens" response.

Ambulance Victoria Barwon South West regional director Simon Thomson said the improvements had been the best in Ambulance Victoria's history.

Mr Thomson said that the improvements followed recent reforms and significant investment in ambulance services.

Minister for Ambulance Services Jenny Mikakos said the investment upgrades facilitated paramedics arriving on the scene faster.

"Our $500 million ambulance investment means an additional 450 paramedics, extra vehicles and new and upgraded ambulance branches, which helps us shave precious minutes off response times in places like Warrnambool, Moyne, Colac-Otway and Corangamite," she said.

"Year after year our ambulance response times get quicker and our hardworking paramedics reach life-threatening emergencies faster, giving Victorians the best possible chance of surviving a severe illness or injury."

Warrnambool paramedics remain among the fastest in the state with time-critical response times decreasing to an average 9.24 minutes, and 92.5 per cent of Warrnambool's triple-0 calls have a paramedic on scene within 15 minutes.

Colac-Otway saw 67 per cent of emergencies attended to in under 15 minutes, up seven per cent from the 2016/17.

The average response time dropped by almost two minutes to under 15 minutes.

Moyne Shire also saw improvements with the average response time falling to 17 minutes, 29 seconds.

Corangamite paramedics are edging towards reaching half of patients within 15 minutes, moving to 47.9 per cent, and improved their average response time by 50 seconds.

"We are working hard to continue to improve our response times, which improved year-on-year in almost three-quarters of the Local Government Areas across the state," Mr Thomson said.

"Our aim is to give every patient the best care, every time.

"Improved response times are leading to improved patient outcomes, especially for cardiac arrest, stroke and trauma patients."

"We have introduced new senior paramedics to the Corangamite and Southern Grampians shires to improve community response and ambulance availability.

"We have also expanded our partnership with the CFA to deliver emergency medical response in regional areas and introduced more patient transport services across the state and introduced the GoodSAM program to improve cardiac arrest survival."

Meanwhile, Southern Grampians and Glenelg experienced slower response times than previous years. 

The faster response times have not covered the entire region with Southern Grampians and Glenelg experiencing slower response times and percentage of time-critical cases being attended to within 15 minutes.

In Glenelg, the number of sub-15-minute time-critical cases dropped three percent from the year before, while Southern Grampians' response time slowed by less than a minute. 

Mr Thomson said smaller volumes of cases resulted in larger fluctuations.

"We are continuing to improve the responsiveness of our Ambulance Community Officer teams in those areas and welcome interested community members in Penshurst, Glenthompson, Coleraine and Balmoral to get involved in their local Ambulance Team," he said.

Mr Thomson said members of the community could assist paramedics by providing accurate location and description of the incident, and access to a property and the patient.

"Bystanders are the critical first link in the 'chain of survival'," he said.

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