More than 50 children have died in NSW over 10 years from diseases that could have been prevented through immunisation.
An analysis of child deaths from 2005 to 2014 has identified 54 children who died from infectious diseases for which a vaccine is currently available.
But most preventable deaths were caused by influenza and meningococcal B, which have vaccines that are not provided free of charge under the national immunisation program and have to be privately purchased, unless the child has underlying medical conditions.
The Child Death Review Team, which commissioned the research as part of its annual review of child deaths, has recommended that parents wishing to reduce their child's risk of contracting influenza or meningococcal B to discuss this with their doctors.
The national immunisation program covers 16 infectious diseases such as measles, mumps, polio, rubella, diphtheria, meningococcal C, varicella and rotavirus which are provided free to all children.
In recent years there have been deaths from pneumococcal disease, meningococcal disease, pertussis, varicella and influenza.
The analysis by the National Centre for Immunisation Research and Surveillance (NCIRS) found that many of the children who died from vaccine-preventable diseases could not have been immunised, either because they were too young, they were affected by a strain of the disease not covered by the vaccine or the vaccines were not available in their lifetime.
This left 23 deaths from diseases that were preventable or potentially preventable by vaccination, most often from influenza - which can't be given to children aged under six months - or meningococcal disease.
Five children died from meningococcal and 12 from influenza in circumstances that a vaccine was available and they were eligible to receive it.
In addition, one child died from pertussis, one from hepatitis A and four from pneumococcal disease.
One fully vaccinated child died from pneumococcal disease, in what was considered a vaccine failure.
The annual report of the Child Death Review Team, which is part of the NSW Ombudsman's office, found 504 children aged up to the age of 17 died in 2015.
NSW Ombudsman spokeswoman Monica Wolf said the overall number of children dying from diseases that were preventable by vaccination was small, but the ombudsman supported the recommendations surrounding the influenza and meningococcal B vaccines, she said.
"They're not provided free of charge so that's something they could make available and we would support," Ms Wolf said.
Given that many deaths occurred in babies too young to be vaccinated, people who were going to be in contact with those children needed to be aware of the risks, she said.
About one in five deaths in 2015 were caused by injury, including 26 children who died by suicide, 33 who died in transport accidents, eight who died from abuse and nine children who drowned.
The report also showed that the mortality rate from suicide among 15- to 17-year-olds was the highest that it has been since 1997 and Aboriginal and Torres Strait Islander children were more likely than non-Indigenous children to die from nearly every cause.
All but five children who died by suicide in 2015 were aged 15 to 17, and the youngest was 13 years old. Most had previously attempted suicide or threatened to do so.
The report said that while about half of them were receiving support, sometimes this was through a mixture of public and private sources and these were not always well co-ordinated.
It also pointed out that there was no focused suicide prevention plan for young people in NSW.
But the number of children who died from natural causes was the lowest that it has been in 15 years, largely because of a decrease in infant mortality.
Fewer children are dying in the first year of life, partly because of medical advances but also because there are fewer fatal diseases due to universal immunisation programs.
