Police said the couple had married four days ago in the United States and were on honeymoon in New Zealand.
Waikato Road Policing Manager Inspector Leo Tooman said the crash was an "absolute tragedy".
"My heart goes out to the family and friends of the couple."
Investigations believed the couple had overtaken a stationary green vehicle that was giving way at the SH3 intersection before turning right towards Te Kuiti, Mr Tooman said.
He asked for the driver of the green vehicle to come forward to police.
To give information on the crash call Waikato Serious Crash Unit on 07 850 7050.