Victoria's ambulance service has named its next chief executive after the body's long-overdue annual report highlighted the scope of its deteriorating response times.

Department of Health deputy state controller Jane Miller will become Ambulance Victoria CEO late next month, replacing Tony Walker after he stepped down in October.

She has previous experience working in senior roles at Melbourne's Royal Children's Hospital for 13 years, including as acting chief executive and chief operating officer.

"I know Jane will be an inspiring and inclusive leader as she steps in to drive the important cultural and operational strategic reforms currently under way at Ambulance Victoria," chair Shelly Park said on Wednesday.

Professor Shelley Dolan will continue to serve as interim CEO until Ms Miller joins the service.

It comes after Ambulance Victoria's annual report was tabled in state parliament late on Tuesday, among a cache of 265 documents.

It shows the service responded to more than a million incidents by road and air in 2021/22 and worsening response times for the most serious "code one" incidents.

Some 67.5 per cent of those events were responded to within the benchmark of 15 minutes or less, compared with 77.2 per cent the year before. The statewide average target is 85 per cent.

Overall, the average response time for code one incidents was 15 minutes and two seconds, following three consecutive quarters of record demand spurred by COVID-19.

"A 16.7 per cent increase in time-critical code one emergencies had an impact on our performance," former chair Ken Lay and Mr Walker wrote.

"While we know more needs to be done to meet our targets and community expectations, it is important to recognise that response times are only one measure of a quality ambulance service."

A separate annual report into the state's emergency call-taking service showed 64.2 per cent of ambulance calls were answered within five seconds across 2021/22, below the monthly benchmark of 90 per cent.

The Emergency Services Telecommunications Authority was just under that goal in 2020/21 at 87.7 per cent and also linked the blowout to COVID-related demand, particularly during the Omicron outbreak.

The authority conceded examination of its service delivery was justified after two independent reviews, including one that linked 33 deaths to ambulance call delays.

"ESTA was not performing to the standard expected by the community or its partners. It was clear, parts of ESTA needed to change," the report said.