Elisabeth Ballerman of the Health Sciences Association of Alberta says Horne has delayed the report for another month.
The Health Quality Council was asked to look into EMS operations a year ago and the report was due last October.
Ballerman believes the review will confirm what frontline workers have been saying about slow response times.
She also points to figures from Alberta Health Services that she says show a widespread failure to meet targets for wait times in hospital emergency departments in Calgary and Edmonton.
Ballerman has written to Horne to say further delaying the report means problems won't get addressed, putting Albertans at unnecessary risk.
Ballerman notes that a peak-hours ambulance has been cut in Camrose, southeast of Edmonton, to save money.
She says it's another example of a big problem with health care in Alberta.
"Of course, (the province) should always be looking at spending its money wisely. But we have a system that has been stressed for a long time, and to cut direct, patient-care services when they're already inadequate, is completely a bad idea."
On a related issue, the central Alberta community of Lacombe is no longer sending its volunteer firefighters on medical first-response calls.
The mayor says crews will continue to provide first-aid at fires and collisions, but will not take emergency calls involving heart attacks, strokes and drug overdoses.
Mayor Steve Christie says it would be irresponsible to ask firefighters to carry out a service they are not fully qualified to perform.
(CHQR, CHED, The Canadian Press)