A cyclist was critically injured and three others hurt when a car ploughed into a pack of 20 riders in Auckland yesterday.
Cyclists who were with the injured men described the scene as "absolute carnage."
"All you could hear was the sound of carbon and bodies falling everywhere ... they were crashing all over the place," said Max Horley, who was riding behind the injured men.
Cyclist Maryanne Bawden described: "Bits flying, the noise, and then my friends lying on the ground."
The seriously injured rider, Auckland civil engineer Greg Paterson, was last night in Auckland Hospital with critical head injuries.
Police said the serious crash unit was investigating the accident on Tamaki Dr in St Heliers, a popular waterfront cycling route.
Charges were likely to be laid against the female driver.
Peter Restall, who was leading the group, said Paterson was an experienced rider who had previously taken part in the 160km Lake Taupo Cycle Challenge.
He was riding yesterday with a social cycling group, the Pickled Pedallers.
Paterson's wife Claire had flown to Christchurch yesterday morning but rushed back to Auckland to be at his bedside.
His two adult children, who are studying in Christchurch and Dunedin, were also flying to Auckland yesterday.
Another rider, Dave Woods, suffered broken vertebrae in his neck, broken ribs and facial cuts.
A third rider, Kevin Marsh, received a deep gash to the knee and a broken kneecap needing surgery. The fourth man, Steve Lobb, also broke his collarbone, a shoulder blade and a thumb.
Witnesses to the crash said the vehicle was turning from Cliff Rd on to Tamaki Dr when it collided with the pack, who were riding from the waterfront towards Vale Rd.
They said the car appeared to slow down briefly before speeding towards the cyclists.
"She accelerated into the middle of the group, just cleaned the guys up," said John Cooney.
The driver was "roundly abused" by the riders when she stopped.
Police inspector Willie Taylor said the driver appeared to have driven through a compulsory stop before colliding with the group.
The driver, who stayed at the scene and tried to help, was being interviewed "with a view that there is some fault."
He said the incident was concerning. "Hundreds of cyclists use this road at the weekend. The intersection is fairly clearly marked and the driver will have some questions to answer."
Cyclists called for urgent action to provide a safe cycling track in the wake of the collision.
"Cars and cyclists don't mix," said Restall.
"It's my firm belief that if they can't close a road for an hour early in the morning, then the most ideal solution would be a dedicated cycle lane."
Cycle Action Auckland co-chair Barbara Cuthbert agreed cyclists needed dedicated track facilities - but motorists should also respect their right to be on the road.
"It's about better driving habits in New Zealand firstly, and that includes respecting cyclists."
Cuthbert said Tamaki Dr was a regular source of conflict between cyclists, pedestrians and traffic.
Most riders avoided using a dedicated cycleway on the pavement because of the number of runners and walkers.
"There isn't an instant solution for it, but it's certainly an issue that needs to be addressed."
Cycling Advocate's Network co-chairman Axel Wilke said lowering urban speed limits should be considered. The move has successfully lowered the road toll overseas.
"We don't need to reinvent the wheel, we just have to look at what works elsewhere and how we can implement it here," he said.
Unless speeds were lowered, cyclists would continue to be killed.
* Fatal cost of riding your bike
Seven cyclists have been killed so far this year on New Zealand roads.
Last year 10 riders were killed and almost 900 injured, with most crashes occurring at intersections on urban roads.
Last weekend cyclist Frank van Kampen, 46, was killed after being struck by a car near Otaki.
A 34-year-old cyclist was killed last month in a hit-and-run accident near Leeston, Christchurch.
Another Christchurch crash took the life of a 19-year-old cyclist in July.
Two cyclists have been killed in the Bay of Plenty, one in a May accident at a Mt Maunganui roundabout, and another following a crash involving a logging truck near Te Puke in March.
Two Dunedin cyclists have also lost their lives - one after colliding with a car in the city in March, and another in a crash outside of Mosgiel in June.