The dead woman's husband was flown to Waikato Hospital and was today in a serious but stable condition.
The pair, in their 50s, had picked up their rental car in Auckland.
Alcohol and speed were not believed to be factors, Mr Hamilton said.
Waotu South Rd resident Sharon Edwards knew the intersection of Old Taupo Rd and Waotu Rd very well and said locals knew to treat it with caution due to its unusual layout.
"It's quite dangerous if you're not watching what you're doing. You come around a corner and you've got one road going straight through and one to town. And if you're not watching you can run into someone."
She hadn't heard of any crashes happening in that particular spot before.
"There probably has been but I haven't heard of any."
The Taupo Police Serious Crash Unit would be looking into whether fatigue and distraction were factors but would not have further details until after they spoke to witnesses today.
The crash occurred on a rural 100km/h stretch of road that was not a typical spot for crashes in the region, Mr Hamilton said.