Utah couple Tammy and Richard Barnett were on "the trip of a lifetime to New Zealand" before yesterday's fatal crash, family say.
The family are now fundraising to support Dr Barnett, who was injured in the crash, and cover funeral expenses for his wife.
Tamara Garlick Barnett, known as Tammy, was killed in the collision at 5.30pm yesterday near Hamilton, along with friends Ruth-Ann and Mitchell Peterson, known as Mitch, also from Utah.
The two couples were both well-known in the small community of Richfield, and were members of Church of Jesus Christ of Latter-Day Saints.
A Go Fund Me page for the Barnetts asks family and friends to band together to "make this time a little easier to bear".
"Our dearest wife, mother, daughter, sister, aunt, grandmother and friend Tammy tragically left us while on the trip of a lifetime to New Zealand with her beloved husband Richard.
"Tammy had an incredible energy about her and will be sorely missed."
The page, set up this morning, had raised $1900 by this afternoon.
Dr Barnett is an orthodontist with a practice in Richfield, Utah, and a member of the Richfield City Council. He and Tammy have four children and four grandchildren.
A spokeswoman for Waikato Hospital today said he was in a stable condition and had been moved to a ward.
A friend of both families, Ryan Peterson, said Dr Barnett had posted on Facebook when they arrived in the country on Monday.
He wrote: "We made it to New Zealand, wish I could say the same for our luggage, or at least Tammy's."
Dr Peterson, of Monroe, Utah, was an optometrist who also practised in Richfield. He and Mrs Peterson have five children - two daughters and three sons, ranging in age from 26 to 8.
Ryan Peterson said the Petersons, of whom he is a distant cousin, were also well-known and respected.
"They're just two great families, very involved in the community, in a small town in Utah, and the community is going to miss them," he said.
"They were happy, funny, and always joking around people."
An off-duty policeman on his way home was the first person to come across the crash at the intersection of SH39 (Kakaramea Rd) and Tuhikaramea Rd, west of Hamilton.
Police Waikato road policing manager Inspector Jeff Penno said that officer raised the alarm and gave first aid until paramedics arrived.
"Initial indications are that a blue Toyota Highlander car with four persons on board heading north on SH39 has turned right, across the path of a southbound truck and trailer unit, at the intersection with Tuhikaramea Rd."
He said other vehicles were travelling "in convoy" with the tourists, and were witness to the crash.
Mr Penno would not say if the occupants were wearing seat belts.
He said the investigation would be done as quickly as possible because the sole-survivor was a tourist.
Mr Penno said police extended their sympathy to the families of the victims.
"This is an absolute tragedy on so many levels," he said.
"Those people were tourists to our country. We live in the most beautiful country in the world and it's only natural that people want to travel to our country, and that brings a whole pile of challenges with it."
Members of the Mormon Church in both countries were rallying to support the families today.
Richard Hunter, Pacific area director of public affairs for the church, confirmed the victims had been visiting the Hamilton branch.
He said the church was currently gathering information about what had happened and may have comment later.
Stake president Joseph Cottle, a Mormon church official in Utah, said Thomas Sutcliffe, stake president from the Hamilton Grandview church, phoned him early this morning to inform him of the crash.
Dr Peterson was a bishop in the church.
Mr Cottle said the couple had been excited about their trip, which included a cruise and a stop in Melbourne.
"They are just a great family," Mr Cottle said.
"I taught many of their children in high school, and have a deep love and affection for both of them."
