Police are speaking with a "person of interest" after a woman was seriously injured in a hit-and-run in Masterton.
The woman was taking her young son to his first karate lesson when she was struck by a black car on Te Ore Ore Rd about 5.15pm.
Police said the woman was seriously injured.
A witness said the woman was dropping her son off at a karate class at the community hall across the street from Wairarapa Hospital.
Goju Ryu Karate instructor Steve Riley said he had never met the woman but believed she was bringing one or both of her sons to their first karate lesson.
Two boys at the scene were aged about 4 and 8, he said. They were distraught, and he brought them inside to get them away from the crash. A couple of cars had stopped to help the woman.
"I didn't see anything but I just helped the little boys who were there," he said.
"The boys were really upset, so I took hold of them and took them away."
The children were picked up later by their father, Riley said.
A Wairarapa District Health Board spokeswoman said the woman was in her early 30s and was with her young son.
The child was not injured, but was assessed by medical staff, she said.
The woman was taken to Wellington Hospital by the Life Flight Westpac rescue helicopter.
She was described as being in a "serious but stable" condition when she was picked up by the chopper.
Masterton police said the car would have suffered "significant damage" in the crash.
"The vehicle involved in the incident has left the scene," police said. "[It] is described as a black older model, possibly hatchback car."
Police said they were speaking to someone in relation to the crash, but still want witnesses to call Masterton police on (06) 370 0300 or Crimestoppers on 0800 555 111.