WA's Transport Workers Union is warning of what it calls a dangerous culture of over-the-counter stimulant use and drivers being forced to skip mandatory rest breaks in the state.
The union alleges a trucking firm based in Perth's southern suburbs has coerced drivers into recording breaks they did not take in order to comply with WorkSafe standards.
Drivers must instead complete load haulages in a shorter amount of time.
Under WA law if a driver is engaged to transport goods which requires a working period of seven-and-a-half hours, the driver is entitled to a half hour break.
It is understood workers were threatened with disciplinary action if they did not comply, and a number of drivers have turned to over-the-counter caffeine stimulants as a way to get through long shifts without a mandatory break.
A TWU spokeswoman said the allegations made against the business were not unusual, and were representative of a broader problem in WA's trucking industry.
"Lethal pressures and constant demands from big business, wealthy retailers and manufacturers mean truckies are eleven times more likely to be killed at work than the average for all other workers," she said.
"This pressure sees transport companies and drivers forced to cut back on maintenance, drive long hours, speed and skip mandatory rest breaks.
"Consumption of drugs like No-Doz designed to increase alertness are just further evidence of the pressure, coming from the top of the supply chain, that is put on drivers."
A No-Doz tablet contains around 100 mg of caffeine, which is equivalent to a cup of coffee. When taken in high concentrations, it can result in elevated blood pressure, heart palpitations and fatigue.
The Mental Health Commission said there was potential to become addicted to the substance, and operators of heavy machinery should be especially careful and consider their intake.
"Taking stimulants while driving could give a driver a false sense of confidence, increasing risk-taking behaviour, and not necessarily increasing driving ability. Stimulants can also impair sleep and cause fatigue, increasing the risk of having a crash," a spokeswoman said.
A WorkSafe spokeswoman said the watchdog not able to monitor the use of drugs to stay awake by drivers, but it was up to the employer to implement drugs and alcohol testing to comply with their general duty of care.
"WA has fatigue laws that apply to commercial vehicle drivers, and these specify the amount of non-work time that must be taken by commercial vehicle drivers," she said.
"The reason laws were created to control fatigue management is that fatigue can have dangerous effects on anyone operating a vehicle. This can range from loss of concentration to a driver falling asleep at the wheel and injuring him or herself or other road users."
However some Perth truck drivers said No-Doz and other caffeine stimulants had become an industry necessity in order to complete extended shifts with no break.
The Road Safety Commission said while the organisation was unable to comment on the anecdotal reports of inappropriate use of stimulants by drivers, they discouraged any driver from misusing any form of stimulants while on WA roads.
"Truck drivers, who travel long distances, are particularly vulnerable to the effects of fatigue and need to take regular and proper rest breaks throughout their journeys," Commissioner Kim Papalia said.
"Road Safety Commission teams have travelled around the State in recent months to discuss road safety issues with trucking groups and local governments, with a view to introducing sophisticated road-side rest stops for truck drivers."
A TWUWA spokeswoman said it was important all drivers contact WorkSafe or the Union if they had not been allowed to take a mandatory break while on shift.
"Unfortunately, drivers have little recourse when they're forced to do things by employers that they don't agree with, without putting their jobs at risk," she said.
"If drivers are being forced, or even encouraged to engage in behaviour like recording legal breaks that did not happen, they should contact the site delegate or the local TWU Branch and alert them of such actions."
TWUWA WA state secretary Tim Dawson said there needed to be greater scrutiny placed on the industry in order to prevent the potentially dangerous practices that appear to be commonplace in WA.
"Nothing has been done to make roads safer since the Turnbull Government abolished the Road Safety Remuneration Tribunal (RSRT) almost 12 months ago," he said.
"An independent body like the RSRT is still needed to regulate this industry and hold major clients to account."
Safe Work Australia statistics showed transport workers had the highest workplace deaths compared with all other industries, with 63 transport workers killed in 2016.
A Safe Work Australia report also showed that 583 truck drivers were killed between 2003 and 2015.
WA Police said they did not have plans to test for caffeine-based drugs in the future.
