Working families are increasingly seeking support from the Wellington City Mission.
City Missioner Murray Edridgesaid rising rental costs in the capital mean many working families have little left over for other expenses.
Mr Edridge said the added pressure of finding money to cover the Christmas holiday period was putting these families into financial strife.
"The numbers are increasing and they are changing, the demographic is changing so people we wouldn't previously have seen we are seeing, there's no sense that in the near future that's going to change," he said.
"Accomodation in Wellington in particular is incredibly challenging."
Many turned to debt at this time of year, which stings them in February when back-to-school costs and rental price increases coincide, he said.
The charity has budget advisers available to assist people if they get into financial difficulty in the coming days and weeks.
Yesterday, the Auckland City Mission hosted a Christmas feast for around 2000 people.
City Missioner Chris Farrelly said, like Wellington, it was a diverse group of people who came for a meal.
"There's people who are alone, people who have experienced some major trauma in their life - often it's violence. We have people who have just lost a loved one and this will be their first Christmas alone," Mr Farrelly said.
"There are people who have just been released from prison and are trying to reconnect. There's also people who've been expelled from Australia and we're welcoming them home.
"There are old people, young people, people of every ethnicity, of every religion. What happens here is, once people come through these doors, those differences somewhat evaporate and we are just one community sharing something very special together."