Mr Key made the comments this morning at a reopening ceremony for the Mangere Refugee Resettlement Centre, which has been rebuilt at a cost of $15.9 million. He described the redevelopment as a "substantial upgrade".
"This is a very important day for refugees who are resettling in New Zealand," Mr Key said.
"We recognise it is very challenging for people resettling here. It is important we give them the best start possible.
"It is important that people get the care, love and support they need. Some come from very war-stricken or terrible circumstances and need a lot of support.
"There are a great many stories of families coming here and doing well and making a real contribution to New Zealand society. But it is important to resettle refugees around the country, not just in Auckland."
This month, the Government announced the annual refugee quota would be increased from 750 to 1000, effective from 2018.
About 30,000 people had stayed at the resettlement centre since it started operations in 1979 - three years after the quota was last set.
The new buildings would be able to support a sudden intake at short notice.
Refurbishment work had taken place in stages, and the new design included a soccer field and more open green space.
The centre's opening comes ahead of World Refugee Day on Monday, which will be marked with events in Parliament and around the country.
Red Cross, the primary provider of community refugee resettlement here, is calling for Kiwis to "stand in each other's shoes" to mark the day.
Immigration Minister Michael Woodhouse said the original Mangere facilities were built during World War 2 and were "well past their economic life".
The Government had invested a total of $24.7 million in the project, he said.
"This Government is totally committed to fulfilling its international humanitarian commitments to provide protection to refugees," Mr Woodhouse said.
All refugees spend their first six weeks at Mangere where they undertake a comprehensive reception programme that prepares them to live and work in New Zealand.
The refurbished centre can accommodate between 210 and 220 people for each of the six refugee quota intakes every year.
Labour leader Andrew Little said the new facility was impressive but stressed he felt New Zealand could still do better than the recently announced increase in the annual refugee quota from 750 to 1000.
"This centre here speaks to the world that we are ready to do our bit," he said.
"But we can still increase our quota. We can double it to 1500 and still be as good at refugee resettlement as we have been in the past few decades."
Faisal Farghaly, 45, escaped terror in Sudan to move to New Zealand two years ago with his wife and two young children.
The family spent six weeks at the old Mangere centre before being resettled in Mt Roskill. He is now studying building management.
"It is very nice here," he said.
"New Zealand is our piece of paradise. My family is safe and happy here and we hope to stay for good."
