A Porirua mother drove almost 100km before she realised her children were no longer in the car.
The woman and her children were on their way home from a holiday in Hastings when she stopped to use the toilet in Masterton about 10pm yesterday.
She left her 10-year-old boy and 6-year-old girl in the back of the van, thinking they were asleep, Senior Sergeant Carolyn Watson of Masterton police said.
"She went into the toilet, came out, got back into her van and drove home to Porirua, and then discovered that they weren't in the van. So she was obviously extremely distressed and hysterical and contacted the police," Ms Watson said.
The children were found straight away by two young women, who took them to Masterton police station about 100m away.
The mother called police as soon as she got home to Porirua about 11.30pm.
"She turned around and drove straight back to Masterton and picked them up."
The children, who were reunited with their mother about 12.30am, had been "pretty good" about the ordeal.
"They were a little bit confused but they were pretty good. They were looked after here until she drove back over from Porirua to pick them up."
Ms Watson said the mother had not intended to leave her children behind.
"It's not on purpose and she was quite distressed about it ... It was dark and they were there when she got out of the van," she said.
"She was fairly embarrassed and upset."