Rating agency Fitch Ratings affirmed New Zealand's sovereign debt rating at 'AA' on Tuesday, but downgraded the outlook to "stable" from "positive". The reason for the downgrade was a weaker growth outlook.

"Fitch expects a slight rebound in business investment from its currently subdued level, and continued high net immigration levels to support consumption growth. We assume this will be partly offset by lower dairy production and slower residential investment growth, with stronger construction activity in Auckland unable to fully replace a decreasing contribution from the Canterbury rebuild," the agency said.