Zachary Miller, 23, of Warrumyea Road, pleaded guilty in Warrnambool County Court on Monday to drug and weapon offences.

He was arrested on February 22 this year after a police raid at his home uncovered 166 grams of a methamphetamine, 16 Ritalin tablets, a pen pistol, ammunition, $8500 cash and drug paraphernalia.

The methamphetamine was believed to have a street value of about $115,000.

Miller's criminal history includes jail sentences for trafficking cannabis and methamphetamine in 2016, and further drug and driving-related offending the following year.

Prosecutor Jessica Fallar said dealing in a commercial quantity ordinarily required an immediate custodial sentence unless a special reason could be shown.

She said the maximum penalty for the charge was 25 years' imprisonment.

Barrister Timothy Sullivan said the offending was serious and deserving of a prison sentence.

He said Miller had spent the last 236 days on remand at Barwon - a maximum security prison.

He said during that time, Miller had taken part in a number of courses, had been reading books and going to the gym, was clean from drugs and hoped to study to become a mechanic.

The barrister said Miller used ice for the first time at the funeral of his step father, who died of lymphoma.

He said Miller's mother was now fighting the same disease and had a life expectancy of between three and 12 months.

"There is a tragic irony that (his mother) is now in the same situation and (Miller) finds himself incarcerated for such a long period," Mr Sullivan said.

Judge Mark Dean said he accepted that Miller's mother was unwell.

"And that is a matter of concern for your client," he told the barrister. "It is not an exceptional case but it will make it worse for him."

The judge said Miller was a young offender who had been in jail for almost two years.

He will sentence the man on Wednesday.

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