Victoria's ambulance service has suffered another blow-out in response times for potentially life-threatening incidents.
In its annual report released on Thursday, Ambulance Victoria revealed only 74.8 per cent of Code 1 emergency calls are being attended within 15 minutes - those cases that are time critical and require lights and sirens.
The figure is more than 10 per cent below the state-wide benchmark for 2011/12, and a further drop to a five-year low in failing to achieve the key performance target.
Ambulance Victoria chief executive Greg Sassella has pinned the response time failures on hospital transfer delays and increased demand.
'Like the rest of the health sector, we are experiencing high and increasing patient demand, and it is clear we need to be smart, flexible and adaptable in achieving the best for our patients,' he wrote in the annual report.
The number of patients using ambulances has steadily risen over the past five years.
There were 293,480 Code 1 incidents in Victoria recorded in the 2011/12 financial year, or nearly 15,000 more over the previous year.
The failure to meet response time benchmarks, however, is also being felt at other emergency services.
Victoria's triple zero dispatch provider, the Emergency Services Telecommunications Authority (ESTA), failed to handle big surges in calls during storms and floods, or meet many ambulance and rural firefighter dispatch targets this past financial year.
Not one month in 2011/12 met the dispatch standard required for sending ambulances to critical cases, the justice department's annual report said.
Speeds in dispatching Country Fire Authority (CFA) crews to blazes likely to threaten life or property only exceeded the standard in three out of the 12 months.
And emergency call answer speeds were hit with delays when storms or floods struck Victoria, causing big spikes in the number of calls.
'These spikes contributed to lower monthly call answer performance in all but two months,' the annual report said.
The Officer of the Emergency Services Commissioner is examining the dispatch delays.