Seven-year-old Connor Irvin, from the small Riverina wheat town of Barellan, was killed by a quad bike on Sunday afternoon when he turned a sharp corner on his family's farm and fell off.

He was crushed by the kids' model bike but a nine-year-old family friend who was sitting behind him survived.

Both boys were wearing bicycle helmets and were under supervision, a police spokesman said.

Connor's family, including twin brother Bailey and parents Mel and Dennis, were watching as the crash unfolded and tried to save the boy's life, it is understood.

"He was a very special, soft boy who loved his twin brother Bailey and his sister Shenaye [and] loved his dad's farm," a statement from the Irvin family said.

Connor's death, the 108th quad bike death in six years, has prompted fresh calls for the state government to implement a coroner's 2015 recommendations to make helmets, minimum riding ages and licensing mandatory.

However one of the country's leading quad bike researchers said the machines overall are too dangerous.

"These machines have a very low stability," said Professor Raphael Grzebieta, from the Transport and Road Safety Research Centre at the University of NSW. 

"They are equivalent to driving a heavily overladen truck on a bumpy, undulated terrain. Now would you do that? I don't think so.

"People should wear helmets, yes. As for licensing, that's not the causal factor here. The vehicles have a poor design feature, they are unstable when you hit a rock, a stump or a rabbit hole."

It's understood the bike that killed Connor was a Kanga kids model that did not have any warning stickers on it to reflect the user manual, which states it should not be ridden by anyone aged under 16.

The brochure describes it as an "easy, exciting yet fun way for the kids to get into the four wheel thrill".

Professor Grzebieta was part of a team to develop safety ratings for quad bike models.

"They really need to be ridden by people that have been trained," he said.

A 2015 inquest into nine NSW quad bike deaths found that most involved roll-over accidents on unstable terrain and that most riders weren't wearing helmets.

Deputy State Coroner Sharon Freund recommended the government consider legislation for mandatory licensing or training, helmets, seat belts, age restrictions and safety ratings.

She found there was a pressing need for cultural change among quad bike riders.

However, Fairfax Media understands the state government is keen to stick to its non-regulatory approach and focus on safety awareness.

"We will be implementing a public awareness campaign in the first half of the year that will include information on child safety risks," said Minister for Better Regulation Victor Dominello. "Sunday's incident is a tragic reminder about why this work is so important."

A $2 million rebate package introduced last year offers farmers $500 to put towards the purchase of compliant helmets.

Connor was one of seven people aged under eight to die on quad bikes since 2011.

His adult sister, Shenaye, was among several people who posted tributes online, saying: "Fly high my big blue eyed angel... Promise I'll look after your best mate until you're together again."

Another family member posted "No more. Please no more!" as news filtered through of the second death in the family in as many weeks.

The extended family in Barellan were still mourning the death of truck driver Micheal Irvin, 29, in a truck crash on January 3.

"Its a lot for a small tight knit community to go through let alone one extended family," she posted.