Drug-buying agency Pharmac says it will review its funding of the vaccine for whooping cough, or pertussis, following calls for it to be made available free of charge to more people.
Since the current outbreak began in August 2011, more than 10,000 cases have been reported and three babies have died.
A free booster vaccination has been available to pregnant women since the start of this year, which not only protects mothers but passes on some temporary protection to babies, who cannot be vaccinated before six weeks old.
The Immunisation Advisory Centre says that offer could be extended to cover all who are in close contact with infants - including other family members, healthcare professionals, and childcare workers.
Pharmac medical director Peter Moodie says the matter will be reviewed by its immunisation subcommittee at its next meeting.
He says that will probably be in about three months' time but no date has yet been set.
"This is not a minor decision; this is something which will cost some millions of dollars and I am not saying that's a barrier to actually doing anything but it is a reason to make sure that we're making the right decision."
Doctors at Starship Children's Hospital in Auckland have confirmed a third baby has died.
A six-week-old Christchurch baby died in November last year and another baby before that.
Intensive care doctor Jon Lillie told a conference on immunisation the number was much worse than an outbreak several years ago.
He said all three babies who died were very young and not immunised.
Early Childhood Council chief executive Peter Reynolds says it would be excellent if childcare employees were included.
In the meantime, he is encouraging centres to consider covering the cost of immunisations for their staff, as some already do for influenza.
Radio New Zealand's health correspondent says whooping cough is a highly infectious disease that's spread by coughing and sneezing.