"The Auckland City Mission has been their home for the last 38 years. So just even moving a kilometre away is quite a major event for people.
"It's also a massive move for us because we have to keep services running as they are."
The relatively small, decrepit Hobson St building, which was constructed around a 19th century pub, was no longer fit for purpose. At meal times, many people had to eat standing up "like an old yesteryear soup kitchen", Farrelly said.
General manager of social services Helen Robinson said the city mission had been feeding 100 people twice a day with a single steamer oven.
"One of the joys here at Union St is that we have two steamer ovens, and a gas hob, so even that small difference means we can provide high-quality, good nutritional meals here – which really genuinely makes a big difference for the rough sleeping population.
"One of the biggest concerns we have for that group is that nutritional deficiency of people."
Farrelly said there was also growing demand in Auckland for the city mission's services – for shelter, for food, for healthcare, and for a safe haven from domestic violence.
The Hobson St building will be expanded from two storeys to nine storeys, with accommodation, more detox rooms, a larger medical centre, job training and other services. It will include 80 units which will be permanent housing for chronically homeless people.
Farrelly said that the redevelopment was part of an attempt to eliminate homelessness, rather than just manage it.