Mid-range drink driving offenders will have to blow into a breathalyser to prove they are sober before turning the keys to their cars and the speed camera network on the state's roads will be turned on to catch people using their mobile phones behind the wheel as part of tough state government reforms announced on Tuesday.

After a horror holiday road toll, which saw double the number of deaths on NSW roads compared to the previous year, and an increase in the road toll in the past three years, Premier Gladys Berejiklian's package includes lower speed limits and a crackdown on drink and drug-affected driving and driver distraction.

"All of us have been touched by the heartbreak of the unnecessary loss of lives on our roads," the Premier said. "We've witnessed heartache for families all too frequently in the last two months."

It will be mandatory for people convicted of mid-range drink driving offences to have "interlock" devices fitted to their cars. The technology, previously imposed only on repeat offenders or by a magistrate, stops someone from starting a car if they are detected to have consumed alcohol by blowing into a breathalyser device connected to the car's ignition.