Drink-drivers in Victoria will be ordered to fit alcohol interlock devices to their vehicles at their own cost, under proposed tough reforms.

The law will apply to all drink-drivers unless they can convince the courts they have exceptional circumstances, News Ltd reports.

The interlocks prevent a car from starting if a driver has been drinking and can cost more than $1000.

The Victorian government is drafting legislation and believes the crackdown will catch about 17,000 motorists a year who blow .05 or more.

At the moment, only repeat offenders, drivers who blow more than .15 and those aged under 26 who blow .07 or more have interlocks fitted.

Police Minister Peter Ryan says drink-driving accounts causes 25-30 per cent of deaths on the state's roads and about a third of drink-drivers offend again.