Lachlan McGregor Mitchell, 21, pleaded guilty in the Warrnambool Magistrates Court to escaping from custody.

He is also facing serious charges in both Victoria and South Australia involving firearms, armed robbery drugs and driving offences.

Magistrate Cynthia Toose said it was a pre-arranged escape and a black ute was waiting for Mitchell when he walked out of the youth centre.

Defence counsel Robert Morgan said the escape was only able to happen due to a high degree of luck and lax security.

"In Mr Mitchell's words it was sheer stupidity," he said.

Police said that Mitchell was in the Malmsbury Youth Justice Centre, near Kyneton, serving a 12-month term imposed in March for serious driving and firearm offences.

In September Mitchell was involved in a horror crash with a B-double petrol tanker near Camperdown which resulted in him suffering severe leg injuries and fractures, which will require a full knee reconstruction.

He was charged with an armed robbery in Warrnambool and other serious offences leading to his parole being revoked.

At 1.54pm on November 8 Mitchell escaped from the centre when he walked out through an unsecured area to a waiting ute driven by co-accused Ethan Geebung.

A staff member followed the ute until it started speeding. 

On that afternoon of the escape the ute was involved in two pursuits with police.

One chase was terminated when the vehicle was travelling at 130km/h approaching a school crossing.

The second pursuit stopped when the ute passed a car and then a police vehicle travelling at 150km/h in an 80km/h zone.

Two days later the ute was seen in South Australia carrying false number plates about 1.20pm when it was involved in an accident with another vehicle.

The driver of the other vehicle, a Nissan Navara, was threatened with a shotgun and the two co-accused took his vehicle.

Drugs, cash and other items were located in the black ute. 

On November 12 at 1.25am Mitchell was arrested in South Australia and extradited to Victoria where he has been serving his original sentence in Port Phillip Prison.

Mr Morgan said it was not a sophisticated escape plan and there was no force or coercion involved.

He said his client still faced numerous serious charges, now had an additional three-month jail term, would be serving his original sentence until April and Mitchell would be back in Warrnambool court on March 14.

The magistrate said escaping was a very serious charge and the community expected a further period of incarceration to be imposed.

Ms Toose said it was up to Mitchell to turn around his life when he was eventually released from custody.