The small isolated community is reeling after the latest death, a 3-year-old who died in an accident on the family's farm on Friday afternoon.
Although it was not a workplace accident, WorkSafe New Zealand said it was investigating.
Nine months ago, 4-year-old Reuben Nolan was found dead in an effluent pond on his family farm.
In June 2016, 2-year-old Emily Saunders and a Greymouth man, Barry Petrie, died when the vehicle they were in was swamped by floodwaters in the Poerua River while crossing between farm properties.
Harihari has a population of just over 300.
At least 12 people have died in accidents or tragic circumstances in the area since 2009.
A DHB spokeswoman said yesterday morning, as was customary, it had sent its staff trained in critical incident stress management to help people cope with the shock.
They were available at the Harihari clinic from yesterday.
Westland Mayor Bruce Smith said the community was "absolutely devastated''.
Mr Smith told NZME at the weekend he knew the family of the 3-year-old and was "shattered'' by the news.
"I know the people. I'm aware of the circumstances. It's absolutely tragic.
"My thoughts are for the grandmother and the grandfather and the parents of the wee kid - it's terrible.
"It's going to be incredibly raw. Harihari is a close community.
"I had the unfortunate experience of going to the last wee fellow's funeral and it was gut-wrenching and I don't expect this will be any different.
Police have referred the case to WorkSafe.
Emergency services were sent to the accident scene on Friday afternoon, but some were turned back before arriving.
