A 14-month-girl has died from meningococcal disease, just a few hours after visiting a GP in Northland.

The death of the toddler has been described as one of the saddest cases of the disease by Northland District Health Board medical officer of health Jonathan Jarman.

"This case was an example of how quickly meningococcal disease can progress, and I understand the sorrow and anger the family are dealing with at this time," he said.

The Northland DHB confirmed the girl had died from an "aggressive" meningococcal B strain, and an investigation had since been launched into her death by the Te Tai Tokerau Primary Health Organisation (PHO).

Jarman said the board would help with the investigation, which would look at the GP's management of the case and whether there was anything that could be improved.

“It is crucial that an appropriate process is followed investigating this case. It is neither appropriate nor beneficial to speculate at this stage," he said.

"But we need to keep in mind that GPs see hundreds of children with flu-like symptoms and in the start of the illness it just looks like the flu or a tummy bug... and then it gets worse."

Jarman said the child became unwell on October 14, and was taken to an after-hours GP service, operated by the Te Tai Tokerau PHO at the Bay of Islands Hospital.

She went home and died the next day, in the early hours of the morning.

"There have been three cases of meningococcal disease in Northland this year. This is the first death."

A 13-month-old boy had the disease in early October and an 8-month-old girl had it in March.

Jarman said GPs don't have access to tests for meningococcal disease. Children needed to go to hospital to get a diagnosis, where there are special tests such as a lumbar puncture.

"This is a test where a needle is placed into the spinal cord and a small amount of the fluid of the spinal cord is extracted and sent to the lab.

"You can tell by what is in the fluid, reasonably quickly sometimes, if there is an infection, but it can take a day or so or even longer."

Jarman advised parents that if their child is sick to take them to the doctor, and if they don't get better, take them back.

Meningococcal disease can affect anyone, but it's more common in children under the age of five, teenagers and young adults.

It is caused by the bacterium neisseria meningitidis. There are several different groups of meningococcal bacteria including groups A, B, C, Y and W135.

There were 119 cases - including 13 deaths - in New Zealand last year, with the highest number of rates recorded in the Northland and Lakes DHBs.

Most cases in New Zealand are caused by group B, with 62 per cent of confirmed cases in 2011, and it's more common in winter and spring.

- © Fairfax NZ News