It compares with a fall of 5 per cent between June and August of the same year.
The Whangārei mum, who spoke on the condition of anonymity, said her family could either build on inherited land or relocate a house on the site.
"A lot of beneficiaries don't have the literacy skills so they are more accustomed to living off a benefit rather than trying to go up the ladder," she said.
Convener of the Northland Housing Forum Tim Howard said the entry of new investors was one of the drivers of high rental costs without an uplift in the quality of rental properties in the region.
"It may be good to invest in properties up here but from the point of view of needs of locals, it becomes a major block to either renting or owning a home," he said.
OneRoof editor Owen Vaughan had said Whangarei and the rest of Northland still remained relatively affordable, with first-home buyers making up the bulk of new mortgage registrations in 2018.
Overall, he said, the region remained popular with those seeking to relocate from larger urban centres for more affordable housing options and superior lifestyle properties.
Home affordability report author David White said high house prices in Northland primarily made properties more unaffordable.
"If you're a first-home buyer, buy an entry-level house even if it means doing a bit of work on weekends. Buying a median or upper-level house won't work unless you have a significant deposit," White said.
"The biggest impact for particularly first-home buyers is getting that deposit ready and then there's the servicing of a large mortgage which adds another $50,000 to your mortgage."
White said a three-month analysis may not accurately reflect price trends as demand ebbed and flowed at different times of the year.
National affordability between September and November declined 2.2 per cent.
Southland registered the largest increase in median prices at 15.5 per cent or $36,250, followed by Northland (13.8 per cent or $62,500) and Taranaki (13.7 per cent or $46,500).