According to Cruise New Zealand, two deaths linked to tours from one cruise ship were "highly unusual".
In the first accident, a Mazda driver passed away after a head-on crash with busload of cruise ship travelers in Waikato, police said.
No-one else was injured in the crash, on State Highway 29 near Te Poi, on the Waikato side of the Kaimai Range, about 11.30 a.m. November 22, Tuesday.
About 12.15 p.m., a 71-year-old cruise ship passenger died after she was hit by a truck while on a cycle tour in Tauranga, in the Bay of Plenty.
She died at the intersection of Mirrielees Road and Te Awanui Drive.
Police believed the woman was from the United States.
Both tours were organised for passengers of the Celebrity Solstice, which was docked in Tauranga overnight.
Cruise NZ executive officer Kevin O'Sullivan said the tours usually went off "without a hitch".
"I've never heard of anything like it," he said.
"I couldn't believe it when I heard of the first - then the second. It's just so tragic. It's been a very bad day."
He believed about four people were on the cycle tour. Cruise NZ had sent messages of sympathy to those involved, he said.
Cruise NZ chairwoman Debbie Summers said in a statement the two tour operators involved were "well known and respected".
Tour operators used by cruise ships were closely scrutinised over their health and safety practices.
"We want to reassure cruise visitors to New Zealand that their safety is paramount at all times," she said.
Police are investigating the incidents.
For reports on other Celebrity Solstice ship accidents see at CruiseMinus.com