A cut of $200 million to public health units in Ontario annually would be a "huge step backwards" to frontline services that help to keep communities healthy, says the head of an organization that represents boards of health and medical officers of health.

Dr. Robert Kyle, president of the Association of Local Public Health Agencies, says medical officers are concerned about the magnitude, speed and lack of detail of the cut announced in the Ontario provincial budget last week. The government plans to slash the number of public health units from 35 to 10 over the next two years.

"We prevent chronic diseases, we ensure food safety, immunizations, infectious diseases prevention and control. We focus on substance abuse and injuries, school health. We consider ourselves part of the local, if you will, kind of security infrastructure," Kyle told CBC Radio's Metro Morning on Tuesday.

"If we are doing our job properly, you are not going to see any headlines because you're not going to hear about the diseases that we have prevented. The state of the public health system in Ontario has benefited from the experiences of Walkerton, SARS, pandemic influenza, Ebola, Zika, and now, most recently, opioids and cannabis.

"We are in a very good state in terms of the public health system and providing security locally. And our concern is that this could be huge step backwards from where we are currently."

The Doug Ford government announced in its budget last week that it will plans to cut spending to public health units in Ontario by $200 million annually. (Chanss Lagaden/CBC)

In Walkerton, Ont., he noted that the whistle blower was the local medical officer of health who assessed the health of the community and concluded that the water supply was making local residents sick. In that crisis in 2000, seven people died of E. coli and more than 2,300 fell ill.

Kyle, medical officer of health for Durham Region, said it is not clear how the cut will affect public health units or what the 10 public health regions would look like, but it would likely mean greater distances between offices and a single board of health covering a "huge, huge territory" with a large population.

He said there could be a "lack of connectivity" between public health units and local communities, local priorities could be lost in the regional system and public health units could have "less of a footprint" in communities with the closure of local offices.

"As the focus currently is on improving health care and ending hallway medicine, we are trying to work upstream to prevent people from becoming sick and requiring acute care in hospitals and so forth in the first place," he said. "We are awaiting the details."

A resident walks by a sign showing community feelings in Walkerton, Ont. on May 26, 2000. The whistle blower was the local medical officer of health who assessed the health of the community and concluded that the water supply was making local residents sick. Seven people died of E. coli and more than 2,300 fell ill. (Kevin Frayer/Canadian Press)

In an interview later, Kyle said there is a cost to amalgamating the public health units that already exist and creating new regional health areas. "The numbers do not add up," he said.

The chairs of the boards of health are planning to hold a teleconference on Thursday to discuss the possible deep implications of cut and next steps, he added.

In the budget, the government said: "... the current structure of Ontario's public health units does not allow for consistent service delivery, could be better coordinated with the broader system and better aligned with current government priorities."

"This is why [the government] is modernizing the way public health units are organized, allowing for a focus on Ontario's residents, broader municipal engagement, more efficient service delivery, better alignment with the health care system, and more effective staff recruitment and retention to improve public health promotion and prevention," it said.

The government said "first steps" will take place in 2019-2020, but it plans to establish 10 new regional board of health with "one common governance model" by 2020-2021.