Repeat drink drivers in Western Australia will be forced to install "alcohol interlock devices" from the end of October in a new campaign to crackdown on serious offenders.

The device, which requires a breath test for cars to start, will also be paid for by offenders at a cost of $1600.

Alcohol interlocks will be installed in the cars of drink drivers from October.

Deputy Premier and Road Safety Minister Liza Harvey said on Sunday the devices would be fitted to vehicles once drivers had served drink driving suspensions and would remain in place for at least six months.

As part of the new legislation Ms Harvey launched a public education campaign on the devices in the lead up to the law coming in to force on October 24.