Quad bike riders are being urged to ride safely this summer following a 30 per cent rise in quad bike accident fatalities this year.
A six-year-old, seven-year-old and 15-year-old teenager were among 20 Australians who died from quad bike accidents in 2015, the Australian Competition and Consumer Commission said.
Last year, there were only 15 deaths.
January is the most common month for quad bike deaths among children in Australia, and it also has twice the injury rate of other months.
ACCC deputy chairwoman Delia Rickard has urged people to ride safely - particularly on tricky terrain.
"Many consumers expect that quad bikes can safely go on all kinds of terrain and surfaces," Ms Rickard said.
"Unfortunately, this isn't true - riding on steep slopes, rough terrain and even hard, flat surfaces (such as tarmac and asphalt) may cause the quad bike to become unstable and very dangerous."
Ms Rickard said children were particularly vulnerable in accidents where the quad bike tips or rolls over, with 75 per cent of child fatalities occurring this way.
She said children should never ride bikes intended intended for adults and must be supervised at all times.
The ACCC warning comes after a NSW coroner investigating quad bikes' deadly toll on adults and children last month called on workplace authorities to develop a safety rating system for the vehicles.
Deputy State Coroner Sharon Freund made eight recommendations during her inquest into the "number one killer" for farm workers, including that children aged under 16 be banned from used adult-sized quads.
10 QUAD BIKE SAFETY TIPS
* Train properly before riding a quad bike
* Maintain the bike so it is in safe condition
* Read the operator manual and observe the manufacturer's safety warnings
* Always wear a helmet
* Never let children ride quad bikes meant for adults, even as passengers
* Supervise children at all times near quad bike activity
* Do not carry any passengers on quad bikes meant for one person
* Avoid riding on rough terrain or steep slopes
* Never ride under the influence of alcohol/drugs
* Carry a mobile phone to contact help in case of an emergency.
Source: Australian Competition and Consumer Commission
