Forensic investigators are at the scene marking evidence with cones at the property where the woman was killed.
Two large tents have been erected on her driveway, guarded by a security guard.
Other neighbours in the street said the woman and her son were lovely and kept to themselves.
One woman, who did not want to be named, said the violent incident was a huge shock to the quiet community.
'Stop it, I'll do anything, I'll do anything'
A neighbour of the 20-year-old victim said he heard the attack at his house and people pleading for their lives.
Shane Tredrea said he heard could hear clearly what the victims were saying.
"They were saying 'stop it, I'll do anything, I'll do anything'.
Mr Tredrea said he heard the violent attack take place.
"I could hear punches connecting - the impact of them."
He then saw the alleged offender flee the house.
He did not see any weapon and nobody chased the man, he said.
"Too scared mate."
There had not been a murder in Timberlea before as far as he knew, Mr Tredrea said.
"It's a bit of a shock."
Witness describes horror at axe attack
A woman has told of a narrow escape after a man armed with an axe knocked at her door before going on to attack her neighbour.
The woman, who does not wish to be named, lives next-door to one of the Upper Hutt homes where a man armed with an axe visited in a rampage in which a woman was killed and three other people were injured.
The woman said she was on her computer yesterday evening when the attacker knocked at her door. When he found it locked he went to her neighbour's house.
She said the man attacked her 20-year-old neighbour with an axe as he tried to fend him off.
She said she ran inside and called police.
"I saw it happen.... I saw all the blood, and carried on talking to the police and ambulance."
She said that once the police arrived she stayed with her next-door neighbour until he was taken to hospital. He remained in hospital today with serious injuries.
"I'm still processing, I have never seen anything like this happen before," she said.
Detective Inspector Darrin Thomson confirmed one woman was dead and a 20-year-old male and a 24-year-old male had both been taken to hospital with serious injuries.
He said police were also dealing with a woman who had been assaulted.
Mr Thomson said it was not a random attack.
"He was known to three of the four victims and he is in custody and will appear in court today.
"We are still working through a raft of information as you can probably imagine."
Mr Thomson could not confirm how the man knew the victims.
Colleen Noble says the son of the slain woman tried desperately to seek help. Photo / Mark Mitchell
Son rushes next door for help
The son of a woman slain with an axe rushed to his neighbour's house to try and get help for his injured mother.
The woman, in her 50s, was attacked with an axe in her Timberlea home in Upper Hutt last night.
Neighbour Colleen Noble said she was at home about 8.45pm yesterday when she heard a knock at the door.
"It was our neighbour, he said he and his mum had been attacked by a guy with an axe.
"She said he was holding the axe in his hand and his jumper was wound around his injured arm.
"His hand was covered in blood, and he had a wound on his back... the blood was just dripping... it's still on the carpet."
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She said she bought him inside her house, and called the police.
Ms Noble said they then went outside and waited for police to arrive.
"I wanted to go inside [the neighbour's house] but I just stayed on the driveway.
The scene of the attack this morning was still under guard. Photo / NZME. News Service
"He wanted to go and see if his mum was all right, and then he ran into the house and he started crying I could hear him screaming."
"He was screaming 'he killed my mum' then he came out... I could hear him crying," Ms Noble said while holding back tears.
"When we went back out the front he just had to sit down, he had lost a lot of blood."
Ms Noble said it was all a "big shock".
Ms Noble then said while waiting for police she had a text from a friend who lived nearby.
She said her friend told her she had been attacked by a man in her driveway.
"She texted me and said 'I just got attacked by a guy'."
Anyone with any information was asked to contact the Wellington Police on 04 3812000.