An interpreter who assisted police with a Chinese national who died hours after his release from a police station has told a court she had never seen a detainee treated worse.

Interpreter Yu Shu Lipski, giving evidence at the inquest into the death of Gong Ling Tang, 53, described "blood all over the cell" and Mr Tang rocking in pain on the floor.

"What happened that night, how Mr Tang was treated, shocked me," she said.

Mr Tang's family watched in silence as CCTV footage of his final night, captured at the Dandenong Police Station, was played in the Coroners Court on Monday.

Mr Tang died in hospital from a gastrointestinal haemorrhage in May 2010, the morning after he was bailed from the police station for a suspected intervention order breach and public drunkenness.