A childcare centre in Lower Hutt had to wait almost 30 minutes for an ambulance after a child swallowed a substance from a bottle because the ambulance was sent to Southland by mistake.
The ambulance service in Wellington says Thursday's incident was human error and it does not believe its system is to blame.
A two-year-old boy at the childcare centre had prised apart a children's toy which contained liquid that was not designed to be consumed.
Central Emergency Communications spokesperson Hank Bader said the child choked and tried to spit the substance out.
However, it took 27 minutes for an ambulance to arrive after the call centre operator realised that she had sent it to the wrong address.
The ambulance service has apologised to the childcare centre and the boy's family.
Mr Bader says the operator will be given extra training and mentoring, but was adamant the system does not need an overhaul.
There have been no other incidents in the past year where an ambulance was dispatched to the wrong address from the Wellington call centre, he says.