Other witnesses later described the vehicles involved in the crash as including a truck, motorcycle, ute and minivan.
"I went inside and called 111 and they said 'do you want the police, ambulance or fire?' I said, 'I think we're going to need all of them'."
The 56-year-old said a number of people emerged from a van, which was "pulled to bits".
There was a large response from the emergency services, with some people trapped in the vehicles.
When the ambulances arrived, victims could be seen sitting on the side of the road with blankets, "in shock obviously".
Ward said roadworks were taking place this morning, and it looked like the vehicles were waiting at a stop sign when a truck came up from behind, didn't see them and ploughed into them.
A motorbike was "just a mess" on the side of the road.
Ward had seen a handful of incidents on the stretch of road, but this was "certainly the messiest".
She was feeling shaky after the crash, and felt for the victims.
"There was a lot of innocent people hurt today, but there didn't seem to be anybody killed so that's a blessing."
At 3.30pm, police remained at the scene near Wairakei, about 1.5km north of Palmer Mill Rd, a statement said.
"A full assessment of the crash is still being made. However, initial reports are that a truck crashed into the back of a vehicle, [and] then shunted a number of other vehicles."
It is understood one of those vehicles was pushed across the road into oncoming traffic.
Police said a report from the scene is that the most severe injury was to a motorcyclist, who has serious injuries.
Between 10 to 15 people were taken to hospitals in Tokoroa and Taupo, and to Waikato Hospital.
Tow trucks were removing damaged vehicles from the scene.
"Local diversions are in place and the road is expected to remain shut for about another hour."
The Serious Crash Unit and the Commercial Vehicle Safety Team are investigating.
St John ambulance spokesman Gerard Campbell said three people were in a serious condition and another 12 had moderate to minor injuries.
The most seriously injured were airlifted to hospital.
Three helicopters, including one from Hamilton and one from Taupo, and three ambulances had been called.
State Highway 1 was closed as a result of the crash to allow all three rescue helicopters to land on the road at the crash scene.
The Rotorua-based chopper flew two patients to Taupo hospital, then uplifted a third patient with serious injuries and flew the 24-year-old man to Rotorua Hospital.
Both the Westpac Rescue helicopter and the Greenlea Rescue Helicopter flew seriously injured patients to Waikato hospital.
The NZ Transport Agency put detours in place about 1.50pm.
