Housing New Zealand did not tell her the next-door flat was going to be tested for contamination until she saw people in full protective suits and masks walking around the property.
"I was standing at the window wondering what was going on. I asked the property manager and he ignored me."
Squatters then moved into the vacant flat and she rang up Housing New Zealand. The property manager told her boarder that the house had tested positive for P contamination, she said.
"I became worried for the health of me and my children and wondered why I had not been informed the place was contaminated."
In December, another company arrived to decontaminate the adjoining property and foul, toxic odours started drifting into her house, Ferrall said.
"The day after they were there, Bryce, myself and the children began feeling unwell with dry throats, sore eyes and disoriented; almost flu-like symptoms.
"I asked another property manager if they could transfer us to another house but they told us we were safe."
Fearing for her children's safety she moved them to her mother's house, and stayed on in the house for a couple of days but was driven out by the odour and continuing to feel unwell.
Christoffersen went into the ceiling to see how the smell was coming into the flat and discovered the roof cavity extended across the two units.
Unable to bear it any longer, she and Christoffersen also moved out and have been staying in their vehicles ever since, as there was not enough room for them to stay at her mother's as well as the children.
She asked her Housing New Zealand property manager if her flat could also be tested for contamination but was told that could not happen until the end of last month.
In the meantime the vacant house was burgled, and her children's toys and other items were stolen.
Early this month, she was told her house had returned a positive result for P contamination.
Although Housing New Zealand had offered to transfer her and test the house before she moved in, she said she didn't trust them any more.
"This whole ordeal has put huge stress on our family, leaving us unsettled and distressed. I have become emotionally drained and financially burdened from trying to find the right help and support over the Christmas season.
"I couldn't give the kids any Christmas presents and have been so upset about the effect it is having on them."
A Housing New Zealand spokesman said they tested a property next door to Ferrall's after its tenants were charged with methamphetamine offences in court. The tests came back positive and the tenants moved out in October.
"The two properties' only connection is by a brick and concrete wall between the two kitchens and it is well proven and documented that meth contamination cannot make its way through such materials."
There was no reason to notify Ferrall about the testing or the decontamination in the adjoining property, or any reasonable basis to suspect her property was contaminated by methamphetamine from next door, the corporation said.
"The only chemical to have been detected in the air at the time of decontamination was paint thinner used to clean window sills in the adjoining property by the decontamination company," the spokesman said.
Ferrall's property was not tested earlier because of the holiday season, but the positive results that came back on February 7 showed the highest concentrations of P were in the rooms furthest away from the adjoining property.
Housing New Zealand said it was highly unlikely the positive result would have arisen from any airborne drift from the other flat.
Housing New Zealand said it understood Ferrall's concerns and would work with her to find her a new property.