A Hamilton man has admitted causing a crash that killed a 39-year-old mother and her two-month-old baby girl.

Ethan Rawiri Collier-Whitewood, 27, of Bader, appeared in the Hamilton District Court on Wednesday, where he pleaded guilty to two charges of careless driving causing death, and two of careless driving causing injury.

He will be sentenced on October 14.

Court charging documents name his victims as Soriah Harper-Griggs and her mother, Mandi Chanel Harper. Collier-Whitewood's occupation is listed as 'builder”.

Police were called to the crash on State Highway 26 at Eureka, between Hamilton and Morrinsville, shortly before 2pm on Tuesday, February 1.

Before they arrived, a man who lives nearby rushed out to find a man, woman, and baby in a black vehicle, which was most damaged in the crash.

People from two other cars had already escaped, said the man, who spoke to Stuff on the basis of anonymity.

He said the man in the black vehicle was distraught but able to move, and the woman was 'cut up” and badly trapped in the driver seat.

All he could do was wait for emergency services.

The driver door had been ripped off in the crash.

The man told Stuff he reached into the back seat to check for the baby's pulse, but it was too late.

Everyone who was able to get out of their vehicle safely had, and all he could do was wait for emergency services.

The three to four minutes felt like an eternity to him.

'The people in the other two cars were just in shock,” he said.

A further three people were injured in the three-car crash, one seriously and two with moderate injuries, police said in a statement.

The man told Stuff he had lived near the intersection for four years, and was shocked this was the first major crash.

He said maize obscured the view of people coming around the corner from Morrinsville, and turning into Hinton Rd.

The speed limit was 100kmh, which he said was too fast.

The man said motorcycles flew around the corner at 120km an hour, and people overtook each other, forgetting that motorists could be pulling out of Hinton Rd.

-Stuff/Mike Mather.