Ships in Auckland for the Royal New Zealand Navy's 75th anniversary are taking part in training exercises.
The ships are involved in the Ngatahi and Mahi Tangaroa exercises off the east coast of Auckland from yesterday until tomorrow.
Defence Minister Gerry Brownlee says Exercise Mahi Tangaroa will see navies intercept fictitious threats to New Zealand's borders.
Exercise Nga Tahi will provide training for participants who are not a part of the Asean Defence Ministers Meeting Plus grouping, as well as those from Asean navies not involved in Exercise Mahi Tangaroa.
Ships from Australia, Canada, Cook Islands, Chile, China, India, Indonesia, Japan, Samoa, Singapore, South Korea, Tonga, and the United States are coming for the celebrations that gear up later in the week. USS Sampson left Hawaii on November 3 to participate in the celebrations.
"This is a visit by a US ship for the first time in more than three decades," US Secretary of State John Kerry said at a press conference in Wellington on Sunday.
"It represents a new milestone in our relationship and the normalisation of our security co-operation."
On Thursday, the fleet will enter Waitemata Harbour for the biggest single event of the Navy's birthday celebrations, the International Naval Review.
After the fleet entry, a "1000-sailor" march down Queen St will be held on Friday.
On Saturday the formal International Naval Review will be held, during which Governor-General Dame Patsy Reddy will review the assembled ships, in a centuries-old naval tradition. On Sunday, an open day will be held.