A Calgary toddler has died after his family's 911 call via an internet phone service reached a call centre in another city, leaving them waiting for an ambulance, officials said Wednesday.

The family, located in the north end community of Coventry Hills, called the emergency telephone number Tuesday night after discovering the 18-month-old boy unconscious and having trouble breathing. They used a service that transmits calls over the internet.

Their call was answered by a call centre not in Calgary but in the city where their internet phone service provider is based. It's unclear why, but the call was not forwarded to Calgary's 911 call centre.

The family waited 15 to 20 minutes for an ambulance, then asked a next-door neighbour to call the emergency phone number from his land line. An ambulance arrived less than six minutes later.

The toddler was pronounced dead in hospital.

The head of Calgary's Emergency Medical Services, Tom Sampson, said the family did nothing wrong, and his heart goes out to them. He said EMS wants to know why 911 operators in Calgary never received the family's call.

"We need to understand how this connection did not occur and what we can do to ensure that this issue is addressed, not only here in Calgary but frankly across Canada," he said.

Officials remind anyone with internet telephone service to verify the 911 policy with their providers.