Covid-19 Response Minister Chris Hipkins said a shipment of more than 370,000 doses arrived on Sunday, two days ahead of schedule.
The last shipment of 150,000 doses arrived two weeks ago - also two days earlier than planned and as the country's supplies neared zero.
The rollout has been averaging between 100,000 to 120,000 doses a week since the end of May, restricted by the amount of doses arriving into the country.
The size of the latest shipment meant the weekly rate should start to increase - in line with the Government's plans to "ramp up" the rollout over July and August when the biggest shipments were due from Pfizer.
Hipkins said the early arrival had come about thanks to a "complex logistical exercise".
"The arrival came after some dedicated work got the vaccines onto an earlier than expected connecting freight flight from Singapore.
"The Ministry's logistics team then worked through the weekend to co-ordinate with the flight schedule and be ready for the vaccine's arrival into Auckland International Airport."
Vaccines had been quickly processed and sent to the district health board sites most in need.
Fifteen sites received shipments from the newly arrived stock yesterday, while 104 would receive stocks on Monday, Hipkins said.
"Teams on the ground in DHBs have been managing their stocks but towards the end of last week, margins were again getting tight in some of our larger population areas.
"This big delivery - with further significant shipments to arrive during the final two weeks of July and into August - is a massive boost for the national programme."
The large delivery comes as South Auckland prepares for the country's first mass vaccination event at the end of July and start of August.
Over three days 15,000 people will be vaccinated, with the focus to boost Māori and Pasifika vaccination rates that have fallen well behind the national average.
"Demand for the vaccine continues to be high, particularly in our bigger cities, and we've consistently said we want to have the doses out of storage and into arms," Hipkins said.
"With the rollout continuing to sit at around 6 percent ahead of plan, it's important we continue to do everything we can to get supply out to vaccination centres as quickly as possible.
"We expect this momentum to continue over the remainder of July and into August, with Pfizer having committed to deliver more than 1.5m doses into New Zealand next month.
"That'll represents our biggest monthly delivery to date and is fantastic news for the ongoing ramp-up of our rollout.
"We'll continue to manage and monitor vaccine supplies coming into the country against increasing demand as the vaccination programme gathers momentum."
