Samoa's health ministry says the deaths of two babies last year were caused by nurses mixing the wrong liquid with MMR vaccines.
The two nurses implicated in the tragedy, Luse Emo Tauvale and Leutogi Te'o, pleaded guilty to manslaughter last week and will be sentenced later this month.
Director General of Health Leausa Dr Take Naseri said every vial of the vaccine should be mixed with one vial of dilutant, but the vaccine was mixed with something else.
He said he was worried many parents have stopped taking their children to get any vaccines.
RNZ Pacific correspondent in Apia, Autagavaia Tipi Autagavaia, said would not be easy to convince parents the vaccine was safe.
"They are saying they do not want to take their children to the immunisation program because of what they think is going to happen," he said.
Unimmunised children developing kidney problems
A senior Samoan doctor has warned that children who are not vaccinated run the risk of ending up on dialysis with renal failure.
According to Newsline Samoa, the National Kidney Foundation of Samoa president gave the warning while speaking of young people already getting dialysis treatment.
Papalii Dr Sam Petaia said a child under the age of five years and a 10 year old were among adult patients receiving dialysis and this was causing concern to the medical profession.
He said with the Pacific Games coming up in July, it was crucial parents ensured children were immunised.
"A large number of people will be congregating in Samoa during the Games and there is a possibility of someone coming with a communicable disease and it is for this reason parents must ensure that their children are vaccinated to protect them," Papalii Dr Sam Petaia said.
New Zealand nurses to carry out vaccination training in Samoa
Eight New Zealand nurses will go to Samoa this month to re-train all vaccinating nurses.
Elizabeth Powell, from Counties Manukau Health, said the Samoa Health Ministry has asked the New Zealand nurses to visit.
She said they all speak Samoan and would visit district hospitals for on-the-job training.
"How you have to you know [to] check the vials with two people [to] make sure it is the right date the right dose the right drug.
"There is a whole procedure around that. So this is about reconfirming with these nurses that while they are registered nurses that they are fit to practice that they are really, really competent," Ms Powell said.