Police are appealing for witnesses to come forward after a crash in Waikato that has left two women fighting for their lives.
Emergency services were called to the crash on State Highway 3, north of Ohaupo, about 4.40pm yesterday.
Sergeant John Stapleford of the Waikato Highway Patrol said it appeared the driver of a northbound silver Mitsubishi car was passing a van when an older green Ford Falcon sedan began to follow her very closely.
''As the woman completed her passing manoeuvre she moved into the lefthand lane but the driver of the Falcon then cut sharply in front of her, causing the woman to lose control of her car,'' he said.
"We believe that the Mitsubishi then careered across the centreline into the path of a southbound Honda car, resulting in a collision that left both female drivers suffering critical injuries."
Stapleford said the green Ford Falcon did not stop and was seen to drive off at speed.
Both drivers, who are believed to be aged 27 and 72-years-old, were taken to Waikato Hospital by ambulance.
"We don't know for certain that the driver of the Falcon was aware of what occurred and if that is the case we would ask that person to come forward.
"Traffic on SH3 at the time of the crash was busy and we believe there may be several drivers who saw what happened."
Police asked for anyone with any information on the crash or the identity of the occupants of the older model green Ford Falcon is asked to phone the Waikato Highway Patrol base on 07 858 6200 or Crimestoppers on 0800 555111.