Details of the person killed have not yet been released by authorities.
The Police's Serious Crash Unit is investigating.
The official holiday road period runs from 4pm on Friday to 6am Tuesday.
Last year the Labour Weekend road toll was five, from 94 reported injury crashes.
The motorcyclist killed had been taking part in the Greymouth Motorcycle Street Races event when the accident occurred.
He suffered critical injuries after crashing his bike on Herbert St, about 11am.
A St John Ambulance spokeswoman said the rider was being taken to hospital in an ambulance when they died."We were transporting them to hospital in a critical condition when they sadly became deceased."
Authorities are investigating the crash and are appealing for any witnesses to contact police.
People close to the motorcyclist killed started leaving onlinetributes following news of his death.
One friend acknowledged his mate's love of bikes and said it was not a good day at the racing.
He called his mate "a top fella.''
Another simply called it a "tragic day.''
In the quad bike crash, in a bush reserve on State Highway 41, near Kuratau, one person dead and a 28-year-old woman is in hospital.
Three people were on the bike when it rolled down a bank and into a stream about 1am.
The death will be referred to the coroner.
Meanwhile, five people were injured - one critically - in a head-on collision south of Wellington about 11am today.
Emergency services were called to the scene at State Highway 1, just south of Paekakariki, around 11am.
One woman - believed to be the driver of a northbound car - was airlifted to Wellington Hospital with critical injuries, a spokeswoman for the Wellington Free Ambulance said.
Two others who were travelling in a southbound car - including the driver - were taken to the same hospital via ambulance, suffering moderate injuries.
Two other people were treated at the scene, the spokeswoman said.
The road was closed for moe than three hours.
There was also a crash on State Highway 2, between Ridgemount Rd and Matahorua Rd, just after 5pm.
Two cars collided and the drivers of each were taken to Hawke's Bay Hospital with serious injuries.
A police spokeswoman said there were no passengers in either vehicle.
On Saturday, a man was injured in a hit-and-run in Whanganui.
Jesse Minnell, 24, was struck by a vehicle in Anzac Parade at 2.20am on Saturday morning and a 61-year-old man has since been arrested.
Police were attending a reported brawl, between 10-15 people, outside the Red Lion Hotel when the incident occured.
The arrested man will appear on two charges in the Whanganui District Court tomorrow morning.
A police spokeswoman said he faces one charge of wounding with intent to cause grievous bodily harm (other weapon) and one of being an unlicensed driver failing to comply with prohibition.
Mr Minnell is from Whanganui and attended Whanganui High School but has lately been living in Palmerston North while studying at Massey University.
Police said no arrests were made in relation to the brawl outside the hotel.
