The truck driver accused of killing four police in a horror crash on Melbourne’s Eastern Freeway has been charged with drug trafficking.

Mohinder Singh, 47, was charged with culpable driving causing death over the April crash that killed four officers on a routine traffic stop.

On Wednesday police laid another 33 charges against the man, who is currently in custody.

He’s now been charged with four counts of dangerous driving causing death, driving under the influence, and trafficking methamphetamine and cannabis.

He’s also facing other drug-related charges.

Leading Senior Constable Lynnette Taylor, Senior Constable Kevin King and constables Glen Humphris and Josh Prestney were killed while they were impounding a Porsche on the freeway.

Senior Constable Kevin King, Leading Senior Constable Lynette Taylor, Constable Joshua Prestney and Constable Glen Humphris

Mr Singh initially faced court days after the crash, where his lawyer Steven Pica said he was “distressed and saddened” at his actions.

He is due to face court next on October 10 for a committal mention.

-AAP