Hayden Richard Hurst, 28, was originally charged with drink-driving causing the death of Outrega (Tre) Anderson about 7.30am on December 16 near Arrow Junction on State Highway 6.
Last month, police laid a charge of drug-impaired driving causing death, alleging Hurst was impaired by ecstasy.
The charge has now been upgraded to manslaughter, police said in a statement yesterday.
Court documents said Hurst, who was seriously injured in the two-car collision, had a blood-alcohol level of 131mg.
The legal limit is 50mg.
Mr Anderson was the head butcher at Royalburn, owned by Nadia Lim and Carlos Bagrie.
Hurst was remanded on bail to appear in the Queenstown District Court on March 11.