Prime Minister John Key, whose Helensville electorate includes the west Auckland suburb struck by a deadly tornado on Thursday, has extended his condolences to the families and friends of the victims.
Three people were killed when a concrete slab landed on a truck at a new school construction site in Hobsonville just after midday.
"This must have been an extremely frightening situation for many people in the local community," Mr Key said in a statement on Thursday afternoon.
"I'd like to thank the emergency services staff, who are responding to the situation. It's critical they are able to focus on the response."
Mr Key said he was being kept up to date with the situation.
Labour leader David Shearer also expressed his sympathies and thanked the emergency services.
"Our hearts go out to the family and friends of those who were killed. It is deeply shocking to lose loved ones in such a sudden and tragic way."
Labour MPs were already on the ground offering support and help to those affected.