"The two people - a man and a woman - were killed on impact and the driver of the ute walked away with some minor injuries and has been taken to Taupō Hospital," the woman told the Herald.
The woman, who asked not to be named, said the two people who died looked between 25 and 35 years old.
"The ute T-boned the vehicle on the passenger side," she said.
Photos provided to the Herald by the woman show a black Isuzu ute crashed into the car, as fire and ambulance crews respond.
"There was zero traffic. Emergency services took ages, we were told they had been called and then waited another 20 minutes," she said.
A police spokeswoman said the circumstances of the crash, including the movements of vehicles before they crashed, would be subject to investigation and they couldn't comment further.
"The road remains blocked and police ask motorists to continue to avoid the area."
Earlier today, Fire and Emergency New Zealand shift manager Josh Pennefather told the Herald at least one person remained trapped after the collision.
"I can't comment on the extent of the injuries or if there are any fatalities, you'll need to speak to police," Pennefather said.
A police spokeswoman said the road was blocked and motorists were asked to avoid the area.
"Serious Crash Unit has been notified," she said.
Fire and Emergency New Zealand sent two crews, one from Taupō and another from Kinloch after they were called about 11.20am.
Pennefather said an operations support vehicle remained at the scene to assist police with road blocks.
More information would be provided when available, the police spokeswoman said.