Convicted drug boss Tony Mokbel is under investigation for allegedly assaulting a fellow prisoner at Victoria’s maximum security Barwon Prison.

The other prisoner was taken to hospital with a suspected broken nose after the alleged jail assault last week, Corrections Victoria said in a statement on Wednesday.

“A 48-year-old prisoner at Barwon Prison was involved in an alleged assault with another prisoner on 17 April, 2014,” Corrections Victoria said.

Victoria Police are investigating the matter.

It is unknown what sparked the alleged attack.

Mokbel, 48, is serving a 30-year jail sentence with a minimum 22-years for orchestrating a multimillion-dollar drug trafficking empire.

He became a wanted fugitive when he escaped to Europe skipping bail in March 2006 facing serious drug charges.

Mokbel pleaded guilty in 2011 to trafficking large commercial quantities of methamphetamine and MDMA, and inciting an undercover policeman to import a commercial quantity of MDMA, according to Fairfax media.