Ben Cousins told he was lucky he didn't kill someone after crashing car high on meth

A Perth magistrate has told troubled former AFL star Ben Cousins he was lucky not to have killed or seriously injured someone when he smashed his car head-on into a truck while high on methamphetamine.

Cousins was sentenced to one year behind bars in late March for stalking and repeatedly breaching a violence restraining order taken out by his ex-partner and mother of his two children.

He spent three-and-a-half days in hospital after the November crash in High Wycombe and pleaded guilty in Perth Magistrates Court on Wednesday to driving under the influence of an illegal drug.

Cousins pleaded guilty to driving under the influence of an illegal drug. Source: AAP

The former West Coast Eagles footballer would have been eligible for parole after serving six months but failed a drug test while in custody so cannot be released until he completes rehabilitation courses, which his lawyer, Michael Tudori, said had taken too long to start.

As a result, the 39-year-old would likely end up serving his full one-year sentence, Mr Tudori said.

The court heard Cousins had 0.75mg of methamphetamine per litre of blood in his system, which the police prosecutor said was well above the level where a driver could concentrate.

"It is lucky no one was killed," the officer said.

The Brownlow medallist also had 0.07mg/l of amphetamine in his system.

"It is lucky no-one was killed," Cousins was told. Source: AAP

Mr Tudori said the crash happened when Cousins had a heavy drug addiction and depression over not being able to see his children, with the restraining order being the trigger that sent him on a downward spiral.

"This offence is all part of the series of offences he's imprisoned for," the lawyer said.

"He said there had been many positive changes in Cousins' life for the first time in many years, including him acknowledging his drug addiction.

Mr Tudori told the court Cousins had "taken and embraced" a job offer from his old employer but would not elaborate when quizzed by reporters.

Cousins would live with his parents when he was released, the lawyer said.

The magistrate agreed it was lucky no one was killed or seriously injured in the crash.

She gave Cousins credit for his early guilty plea but said his drug-driving was serious and in a higher category than the other offences.

Cousins was fined $1200, ordered to pay $2295 in chemical analysis fees and had his driver's licence disqualified for 12 months.