He and Fred Horne spoke at the Alberta Urban Municipalities Association convention in Calgary.
Spearman says it doesn't appear that Horne is willing to change course, but may consider delaying the plan.
The mayor says centralized ambulance dispatch is the No. 1 concern of most delegates at the convention.
He says communities already using consolidated service in southern Alberta are reporting 30- to 45-minute waits.
Spearman says that compares with an average time of six to eight minutes in Lethbridge where fire and EMS officials use local dispatch.
Ambulance wait times in Medicine Hat have increased by 50 per cent, he added.
"People are very concerned about the quality of service," Spearman said Thursday after his meeting with Horne.
"Our time at AUMA has confirmed that ... communities right across the province are concerned about this very same issue. Mr. Horne appears only interested in tweaking by not changing course."
Spearman suggested the issue isn't going to go away.
"We continue to build allies across the province and we think the premier and the minister of health should be listening. The numbers are building, the concern is building.
They have to acknowledge the quality of service that we currently provide and they have to make sure it's maintained."
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