Landslides triggered by earthquake shocks blocked highways leading to the town, and left about 2,000 Kaikoura residents and hundreds of tourists cut off from the outside world, with knocked-out water supplies and sewer systems.
A rescue operation is under way, with military helicopters ferrying people out and delivering food, water, diesel fuel, and other living essentials.
"There's a real imperative to support the town because it can't support itself," Air Commodore Darryn Webb, acting commander of New Zealand's Joint Forces, told the Associated Press.
Answering the plea for help, the US diverted its USS Sampson destroyer to deploy two helicopters to Kaikoura, contributing to the major rescue operation.
The vessel was expected to participate in the 75th anniversary celebrations for the New Zealand navy, initially scheduled for Wednesday. The visit by the US ship is a matter of high importance for both countries as it ends a 30-year military stalemate, following New Zealand's decision to bar nuclear-powered or nuclear-armed ships from using its ports or entering its waters.
New Zealand Defense Minister Gerry Brownlee praised the ship's role in helping quake relief efforts, saying that, "despite the changes to the planned celebrations, it's poignant to see the anniversary marked with such cooperation and camaraderie."
Much of New Zealand lies within the zone of the so-called Ring of Fire, a horseshoe-shaped string of volcanoes and tectonic plate faultlines around the Pacific Rim, where about 90 percent of the world's quakes occur. On February 2014 the island nation was shaken by a magnitude 6.3 quake that killed at least 166 people.
