Drivers in New South Wales will be subject to roadside tests for cocaine, the latest addition to the state’s mobile drug testing regime.

Guardian Australia understands it will come as part of a broader road safety policy announcement. News Corp reported that the premier, Gladys Berejiklian, would announce the new tests on Monday.

In NSW police are currently able to conduct roadside tests for cannabis, amphetamines and methamphetamine or “ice”, and MDMA. The tests itself – a saliva swab – will not need to be changed to test for cocaine.

The move comes after months of lobbying from NSW police. Earlier in January the state’s police commissioner said roadside cocaine testing would have a “positive outcome on the road toll and road safety”.

But statistics suggest cocaine is not a major contributor to roadside deaths caused by drugs and alcohol. According to the NSW Centre for Road Safety, cocaine was associated with 11 road fatalities between 2012 and 2016, compared with almost 300 associated with cannabis, ecstasy and ice.

There were 393 deaths on NSW roads in 2017, the worst result in seven years. The December period saw a number of crashes involving multiple fatalities, including 22 deaths across the country in the fortnight leading up to Christmas.

Annabelle Falkholt, 21, died in a crash on the NSW south coast that also killed her parents and another driver on Boxing Day. Her sister, the actor Jessica Falkholt, remains in a critical condition after having her life support switched off last week.

The high December death toll has focused attention on road safety laws, despite coming at the end of a year in which the road toll across the country reached near-record lows.

The number of deaths per 100,000 people fell to 4.92 in the 12 months to the end of November, which is close to the all time low of 4.9 set in 2014.