Forbes - who has "f--- the authorities" tattooed on his torso - was jailed for a maximum of two years, with a minimum of one year, in the district court in Sydney on Thursday.

Because he has already served about 10 months on remand, he could be paroled as early as June 29.

It was unclear how his parole will be dealt with - Forbes had been on parole when arrested for the manslaughter of bikie Andy Hullick in May 2002.

The parole was due to expire two months ago.

Forbes was also convicted of the January 2002 stabbing manslaughter of Ross Kimball outside the Globe hotel in Dean Street.

The 46-year-old was caught with drugs stuffed down his pants after driving a stolen Mercedes down the Hume Highway on March 30 last year.

The car, which said had been "swerving all over the road, in and out of lanes", pulled up short at a breath testing site at Gundagai about 10.15am.

Forbes parked behind a police truck and was seen moving around inside the vehicle.

"I didn't know that was there, but it doesn't look good," he told officers as they located a small bag of drugs.

A pencil case on the front seat had scales, water and spoons and Forbes tested positive to meth.

He had numbers plates folded over and tucked down his pants, which also contained multiple bags of drugs.

Three capped syringes were also found in his jocks.

Forbes had been delivering the drugs down to Melbourne and was being paid in speed for the deal, with the ice worth about $18,000.