There are concerns some young women aren't being properly vaccinated against Human Papillomavirus, which can cause cervical cancer.
Health Ministry numbers show those who sign up for the vaccine do not always return to get all three required doses.
The vaccine is delivered in schools over a six month period and experts say a fear of needles may be partially to blame.
Emma Comesky decided, with the help of her mother Leigh, to get the vaccine against HPV, but said others at her school had let it slide.
"Some people didn't want to do it so they just got the first one and they didn't do the rest," Emma says.
Public Health Nurse Lorraine Glover said there were also other reasons.
"Often the students are absent when we go back in - today students are very busy with sporting events and though we plan a schedule, we're not always able to fit in with what the school is doing," Ms Glover said.
In 2014, the Ministry of Health said about 89,000 eligible girls opted to vaccinate, but only 82,000 received the full three doses, with statistics showing the drop off rate was worse for Maori and Pacific girls.
Immunologists are currently working on altering the formulation to allow two doses to be effective, instead of three.
The current vaccination programme costs between eight and nine million dollars per year and the ministry says a two-dose system would also save a significant amount of money.