Parents around the country are terrified to leave their home out of fear their baby might become infected with measles if they do.
This comes as Auckland health officials confirmed on Tuesday two unborn babies died after their mothers caught measles during the recent outbreak of the highly contagious disease.
Cases have topped 1307 in Auckland this year, with the majority of those aged under 5.
Hundreds of calls from "extremely worried" parents have been flooding PlunketLine every day, its manager Anne Marie Morris told the Herald, many of them in tears and were too scared to leave their home for fear their baby would catch measles.
This has been the case since late August when the outbreak sky-rocketed, she said.
Morris stressed it was important parents did call the helpline if they were scared and needed some advice.
"Each case is different and it's important they know we are here to help," Morris said.
"Some days we are getting an extra 50 per cent to normal call volume due to concerns of the measles outbreak."
One new mum who spoke to the Herald said she had been forced to put herself on "home arrest" after discovering the immunisation she'd had back in the Ukraine, where she was born, was ineffective and she had no immunity against the deadly disease.
"We were nervous and of course hyper-vigilant even just leaving the hospital with our new family," Irene Direnko-Smith said.
The 35-year-old was unable to get the vaccine when she was pregnant due to the risk it could have on her baby but was immunised with the first dose two days after giving birth to her newborn son.
Despite the vaccine giving her 95 per cent immunity, Direnko-Smith said she was still extremely anxious about leaving the house.
"My baby received no immunity from me when I was pregnant and he can't get protected against the disease until he is 12-months-old when he can get the first dose of the vaccine," Direnko-Smith said.
The North Auckland mum said it was not clear whether her baby could gain immunity through breastfeeding as she was getting contradicting information from her doctor and midwife.
"My doctor told me breastfeeding wouldn't give my baby any immunity and my midwife said it would," Direnko-Smith said.
Dr Nikki Turner, director of the Immunisation Advisory Centre (IMAC), said there was evidence that breastfeeding did give babies some immunity and was not 100 per cent specific to measles.
"Generally, the risk of mums and newborns getting infected with measles from venturing outside is low, but they should try to avoid crowded areas like shopping malls and supermarkets- especially in outbreak areas such as South Auckland," Turner said.
Morris said Plunket had been hearing from a lot of mums who had been cooped up for weeks unsure if it was safe for them to go outside.
"A lot of people were making the decision to stay at home thinking their baby will be less at risk and they would worry less and could instead focus their attention on bonding with their newborn.
"Each case is different but often when parents ask where is safe, we say to them, if you know who you are mixing with and you're in an open air environment, like the park on a fine day, then it's a lot safer.
"It's also okay to ask people for their immunisation status," Morris said.
In South Auckland, Plunket outreach programme manager Sophie Woodger's team were visiting families needing the immunisation who expressed similar concern.
• If in doubt, call Plunket's free 24-hour helpline on 0800 933 922.
The vaccine:
The MMR (measles, mumps and rubella) vaccine is given as part of the free routine childhood immunisations - at 15-months and 4-years. The MMR vaccine is very effective in preventing measles.
About 95 per cent of people will be protected from measles after one dose of MMR vaccine, and about 99 per cent of people who have had two MMR doses will be protected from measles.
People born before January 1, 1969 are considered to be immune to measles.